SSM 2022年8月21日 10点42分
MyBatis 1.MyBatis简介 1.1 MyBatis历史 MyBatis最初是Apache的一个开源项目iBatis,后来更名为MyBatis
1.2 MyBatis特性
MyBatis是支持定制化SQL,存储过程以及高级映射的优秀持久层框架
MyBatis避免了几乎所有的JDBC代码和手动设置参数以及获取结果集
MyBatis可以使用简单的XML或注解用于配置和原始映射,将接口和Java的pojo(Plain Old Java Objects 普通的Java对象) 映射成数据库中的记录
MyBatis是一个半自动的ORM(Object Relation Mapping) 框架
1.3 MyBatis下载 https://github.com/mybatis/mybatis-3
1.4 和其他持久化层技术对比
JDBC
SQL夹杂在Java代码中耦合度高,导致硬编码内伤
维护不易且实际开发需求中SQL有变化,频繁修改的情况多见
代码冗长,开发效率低
Hibernate和JPA
操作简单,开发效率高
程序中的长难复杂SQL需要绕过框架
内部自动生产的SQL,不容易做特殊优化
基于全映射的全自动框架,大量字段的POJO进行部分映射时比较困难
反射操作太多,导致数据库性能下降
MyBatis
轻量级,性能出色
SQL和Java编码分开 ,功能边界清晰,Java代码专注业务,SQL语句专注数据开发效率略逊于Hibernate,但是完全能够接受
2. 搭建MyBatis 注意事项
阿哲,发先学这个要有Maven基础啊,我都没学过Maven,不说了,先去学Maven了
2022年8月23日 03点24分
点一下右上角的M()就可以下载jar包
建表是用软件建的 :
ssm库建了,t_user表建了,都是用图形化界面建的,效率比命令行高啊
创建MyBatis的核心配置文件 习惯上命名为mybatis-config.xml这个文件名仅仅是建议,并非强制要求.将来整合Spring之后,这个配置文件可以省略,所以无关紧要.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd" > <configuration > <environments default ="development" > <environment id ="development" > <transactionManager type ="JDBC" /> <dataSource type ="POOLED" > <property name ="driver" value ="com.mysql.cj.jdbc.Driver" /> <property name ="url" value ="jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC" /> <property name ="username" value ="root" /> <property name ="password" value ="010203" /> </dataSource > </environment > </environments > <mappers > <mapper resource ="mappers/UserMapper.xml" /> </mappers > </configuration >
创建mapper接口 Mybatis中的mapper接口相当于以前的dao,但是区别在于,mapper仅仅是接口,我们不需要提供实现类
1 2 3 4 5 6 7 8 package com.zzmr.mybatis.mapper;public interface UserMapper { int insertUser () ; }
创建MyBatis的映射文件 相关概念:ORM(Object Relationship Mapping)对象关系映射
对象: Java的实体类对象
关系:关系型数据库
映射:二者之间的对应关系
UserMapper.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace ="com.zzmr.mybatis.mapper.UserMapper" > <insert id ="insertUser" > insert into t_user values (null,'admin','123456',23,'男','123456@qq.com') </insert > </mapper >
测试 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 package com.zzmr.mybatis.test;import com.zzmr.mybatis.mapper.UserMapper;import com.zzmr.mybatis.pojo.User;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;import org.junit.Test;import java.io.IOException;import java.io.InputStream;public class MyBatisTest { @Test public void testInsert () throws IOException { InputStream is = Resources.getResourceAsStream("mybatis-config.xml" ); SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder (); SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is); SqlSession sqlSession = sqlSessionFactory.openSession(true ); UserMapper mapper = sqlSession.getMapper(UserMapper.class); int result = mapper.insertUser(); System.out.println("结果：" + result); sqlSession.close(); } }
得到结果:
截断表跟清空表不一样，如果有自增的id属性，截断表会重置该id，而清空表不会
添加log4j依赖：
1 2 3 4 5 6 <dependency > <groupId > log4j</groupId > <artifactId > log4j</artifactId > <version > 1.2.17</version > </dependency >
然后再resources中新建:log4j.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE log4j :configuration SYSTEM "log4j.dtd" > <log4j:configuration xmlns:log4j ="http://jakarta.apache.org/log4j/" > <appender name ="STDOUT" class ="org.apache.log4j.ConsoleAppender" > <param name ="Encoding" value ="UTF-8" /> <layout class ="org.apache.log4j.PatternLayout" > <param name ="ConversionPattern" value ="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) \n" /> </layout > </appender > <logger name ="java.sql" > <level value ="debug" /> </logger > <logger name ="org.apache.ibatis" > <level value ="info" /> </logger > <root > <level value ="debug" /> <appender-ref ref ="STDOUT" /> </root > </log4j:configuration >
笑死,全屏截图,会把副屏的内容也截进去
FATAL(致命)>ERROR(错误)>WARN(警告)>INFO(信息)>DEBUG(调试)
修改和删除用户的功能
创建SqlSessionUtil工具类 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 package com.zzmr.mybatis.utils;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;import java.io.IOException;import java.io.InputStream;public class SqlSessionUtil { public static SqlSession getSqlSession () { SqlSession sqlSession = null ; try { InputStream is = Resources.getResourceAsStream("mybatis-config.xml" ); SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder (); SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is); sqlSession = sqlSessionFactory.openSession(true ); } catch (IOException e) { e.printStackTrace(); } return sqlSession; } }
过程是什么?
在接口中添加字段:
然后在UserMapper.xml中配置:
1 2 3 4 <update id ="updateUser" > update t_user set username='root',password='123' where id = 3; </update >
因为目前没有学到后面的东西,现在的sql语句都是写死的
然后在测试类中测试即可
1 2 3 4 5 6 7 8 9 @Test public void testUpdate () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); mapper.updateUser(); sqlSession.close(); }
很简单,删除操作自己写的:
首先是接口
UserMapper.xml
1 2 3 4 <delete id ="deleteUser" > delete from t_user where id = 4; </delete >
test
1 2 3 4 5 6 7 8 9 @Test public void testDelete () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); mapper.deleteUser(); SqlSession.close(); }
测试查询功能
查询一条数据
1 2 3 4 5 6 User getUserById () ;
其次是UserMapper.xml
1 2 3 4 5 6 <select id ="getUserById" resultType ="com.zzmr.mybatis.pojo.User" > select * from t_user where id = 1; </select >
然后是测试:
1 2 3 4 5 6 7 8 9 @Test public void testGetUserById () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); User user = mapper.getUserById(); System.out.println(user); }
控制台输出结果:
1 2 3 4 DEBUG 08-23 16:22:11,371 ==> Preparing: select * from t_user where id = 1; (BaseJdbcLogger.java:137) DEBUG 08-23 16:22:11,393 ==> Parameters: (BaseJdbcLogger.java:137) DEBUG 08-23 16:22:11,412 <== Total: 1 (BaseJdbcLogger.java:137) User{id=1, username='admin', password='123456', age=23, gender='男', email='123456@qq.com'}
查询多条数据
接口:
1 2 3 4 5 List<User> getAllUser () ;
UserMapper.xml
1 2 3 4 5 <select id ="getAllUser" resultType ="com.zzmr.mybatis.pojo.User" > select * from t_user; </select >
test
1 2 3 4 5 6 7 8 9 10 11 @Test public void testGetAllUser () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); List<User> allUser = mapper.getAllUser(); allUser.forEach(System.out::println); sqlSession.close(); }
得到表中的全部数据:
1 2 3 4 5 6 DEBUG 08-23 16:30:34,972 ==> Preparing: select * from t_user; (BaseJdbcLogger.java:137) DEBUG 08-23 16:30:34,994 ==> Parameters: (BaseJdbcLogger.java:137) DEBUG 08-23 16:30:35,016 <== Total: 3 (BaseJdbcLogger.java:137) User{id=1, username='admin', password='123456', age=23, gender='男', email='123456@qq.com'} User{id=2, username='admin', password='123456', age=23, gender='男', email='123456@qq.com'} User{id=5, username='zzmr', password='123456', age=23, gender='男', email='123456@qq.com'}
核心配置文件 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd" > <configuration > <properties resource ="jdbc.properties" > </properties > <environments default ="development" > <environment id ="development" > <transactionManager type ="JDBC" /> <dataSource type ="POOLED" > <property name ="driver" value ="${jdbc.driver}" /> <property name ="url" value ="${jdbc.url}" /> <property name ="username" value ="${jdbc.username}" /> <property name ="password" value ="${jdbc.password}" /> </dataSource > </environment > <environment id ="test" > <transactionManager type ="JDBC" /> <dataSource type ="POOLED" > <property name ="driver" value ="com.mysql.cj.jdbc.Driver" /> <property name ="url" value ="jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC" /> <property name ="username" value ="root" /> <property name ="password" value ="010203" /> </dataSource > </environment > </environments > <mappers > <mapper resource ="mappers/UserMapper.xml" /> </mappers > </configuration >
在resources目录下新建 jdbc.properties
1 2 3 4 jdbc.driver =com.mysql.cj.jdbc.Driver jdbc.url =jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC jdbc.username =root jdbc.password =010203
最终版的mybatis-config.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd" > <configuration > <properties resource ="jdbc.properties" /> <typeAliases > <package name ="com.zzmr.mybatis.pojo" /> </typeAliases > <environments default ="development" > <environment id ="development" > <transactionManager type ="JDBC" /> <dataSource type ="POOLED" > <property name ="driver" value ="${jdbc.driver}" /> <property name ="url" value ="${jdbc.url}" /> <property name ="username" value ="${jdbc.username}" /> <property name ="password" value ="${jdbc.password}" /> </dataSource > </environment > <environment id ="test" > <transactionManager type ="JDBC" /> <dataSource type ="POOLED" > <property name ="driver" value ="com.mysql.cj.jdbc.Driver" /> <property name ="url" value ="jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC" /> <property name ="username" value ="root" /> <property name ="password" value ="010203" /> </dataSource > </environment > </environments > <mappers > <package name ="com.zzmr.mybatis.mapper" /> </mappers > </configuration >
在idea中能够创建mybatis核心配置文件和映射文件的模板 就是搞个模板啦，没什么难的 mybatis-config
就这样，然后就是把
1 2 3 4 5 6 7 8 9 <typeAliases > <package name ="" /> </typeAliases > <mappers > <package name ="" /> </mappers >
就这两个标签,空出来,因为后面的应用不可能完全一样的.
还有这个mybatis-mapper 该空的就空
1 2 3 4 5 6 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace ="" > </mapper >
说实话到目前为止还没有什么难得
下面使用模板搭建MyBatis框架
很简单,没难度
MyBatis获取参数值的两种方式 MyBatis获取参数的两种形式 ${}和#{}
单个字面量类型的参数 若mapper接口中的方法参数为单个的字面量类型,此时可以使用${}和#{}以任意的名称获取参数的值,注意${}需要手动单引号
UserMapper.xml
1 2 3 4 5 6 7 8 9 10 11 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace ="com.zzmr.mybatis.mapper.UserMapper" > <select id ="getUserByUsername" resultType ="User" > select * from t_user where username = '${username}' </select > </mapper >
测试
1 2 3 4 5 6 7 8 @Test public void testGetUserByUsername () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); User user = mapper.getUserByUsername("admin" ); System.out.println(user); }
还有什么多个字面量类型的参数/map集合类型的参数/实体类类型的参数/使用@Param表示参数,都在下面最终版里面了
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 package com.zzmr.mybatis.mapper;import com.zzmr.mybatis.pojo.User;import org.apache.ibatis.annotations.Param;import java.util.Map;public interface UserMapper { User getUserByUsername (String username) ; User checkLogin (String username, String password) ; User checkLoginByMap (Map<String, Object> map) ; void insertUser (User user) ; User checkLoginByParam (@Param("username") String username, @Param("password") String password) ; }
UserMapper.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace ="com.zzmr.mybatis.mapper.UserMapper" > <select id ="getUserByUsername" resultType ="User" > select * from t_user where username = '${username}' </select > <select id ="checkLogin" resultType ="User" > select * from t_user where username = '${arg0}' and password = '${arg1}' </select > <select id ="checkLoginByMap" resultType ="User" > select * from t_user where username = '${username}' and password = '${password}' </select > <insert id ="insertUser" > insert into t_user values (null,#{username},#{password},#{age},#{gender},#{email}) </insert > <select id ="checkLoginByParam" resultType ="User" > select * from t_user where username = #{param1} and password = #{param2}; </select > </mapper >
还有测试类:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 package com.zzmr.mybatis.test;import com.zzmr.mybatis.mapper.UserMapper;import com.zzmr.mybatis.pojo.User;import com.zzmr.mybatis.utils.SqlSessionUtil;import org.apache.ibatis.session.SqlSession;import org.junit.Test;import java.util.HashMap;import java.util.Map;public class ParameterTest { @Test public void testGetUserByUsername () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); User user = mapper.getUserByUsername("admin" ); System.out.println(user); } @Test public void testCheckLogin () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); User user = mapper.checkLogin("admin" , "123456" ); System.out.println(user); } @Test public void testCheckLoginByMap () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); Map<String, Object> map = new HashMap <>(); map.put("username" , "admin" ); map.put("password" , "123456" ); User user = mapper.checkLoginByMap(map); System.out.println(user); } @Test public void testInsertUser () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); Map<String, Object> map = new HashMap <>(); User user = new User (null ,"zzmr" ,"123456" ,33 ,"女" ,"123@163.com" ); mapper.insertUser(user); } @Test public void testCheckLoginByParam () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); UserMapper mapper = sqlSession.getMapper(UserMapper.class); User user = mapper.checkLoginByParam("admin" ,"123456" ); System.out.println(user); } }
后面可能还会在这里面加,但是目前来说已经很重要了,是值得写进来的
MyBatis的各种查询功能 好家伙，笔记全写代码中了
接口 SelectMapper.java 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 package com.zzmr.mybatis.mapper;import com.zzmr.mybatis.pojo.User;import org.apache.ibatis.annotations.MapKey;import org.apache.ibatis.annotations.Param;import java.util.List;import java.util.Map;public interface SelectMapper { User getUserById (@Param("id") Integer id) ; List<User> getAllUser () ; Integer getCount () ; Map<String, Object> getUserByIdToMap (@Param("id") Integer id) ; List<Map<String, Object>> getUserToMap () ; }
SelectMapper.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace ="com.zzmr.mybatis.mapper.SelectMapper" > <select id ="getUserById" resultType ="User" > select * from t_user where id = #{id}; </select > <select id ="getAllUser" resultType ="User" > select * from t_user; </select > <select id ="getCount" resultType ="int" > select count(*) from t_user; </select > <select id ="getUserByIdToMap" resultType ="map" > select * from t_user where id = #{id}; </select > <select id ="getUserToMap" resultType ="map" > select * from t_user; </select > </mapper >
测试类 SelectMapperTest.java 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 package com.zzmr.mybatis.test;import com.zzmr.mybatis.mapper.SelectMapper;import com.zzmr.mybatis.pojo.User;import com.zzmr.mybatis.utils.SqlSessionUtil;import org.apache.ibatis.session.SqlSession;import org.junit.Test;import java.util.List;import java.util.Map;public class SelectMapperTest { @Test public void testGetUserById () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); SelectMapper mapper = sqlSession.getMapper(SelectMapper.class); User user = mapper.getUserById(2 ); System.out.println(user); } @Test public void testGetAllUser () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); SelectMapper mapper = sqlSession.getMapper(SelectMapper.class); List<User> allUser = mapper.getAllUser(); allUser.forEach(System.out::println); } @Test public void testGetCount () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); SelectMapper mapper = sqlSession.getMapper(SelectMapper.class); Integer count = mapper.getCount(); System.out.println(count); } @Test public void testGetUserByIdToMap () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); SelectMapper mapper = sqlSession.getMapper(SelectMapper.class); Map<String, Object> user = mapper.getUserByIdToMap(3 ); System.out.println(user); } @Test public void testGetUserToMap () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); SelectMapper mapper = sqlSession.getMapper(SelectMapper.class); List<Map<String, Object>> userList = mapper.getUserToMap(); for (Map<String, Object> map : userList) { System.out.println(map); } } }
特殊SQL的执行 到模糊查询了 哎嘿嘿，代码来咯
SpecialSQLMapper.java 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 package com.zzmr.mybatis.mapper;import com.zzmr.mybatis.pojo.User;import org.apache.ibatis.annotations.Param;import java.util.List;public interface SpecialSQLMapper { List<User> getUserByLike (@Param("mohu") String mohu) ; void deleteMoreUser (@Param("ids") String ids) ; List<User> getUserList (@Param("tableName") String tableName) ; void insertUser (User user) ; }
SpecialSQLMapper.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace ="com.zzmr.mybatis.mapper.SpecialSQLMapper" > <select id ="getUserByLike" resultType ="User" > select * from t_user where username like "%"#{mohu}"%"; </select > <delete id ="deleteMoreUser" > delete from t_user where id in (${ids}) </delete > <select id ="getUserList" resultType ="User" > select * from ${tableName}; </select > <insert id ="insertUser" useGeneratedKeys ="true" keyProperty ="id" > insert into t_user values(null,#{username},#{password},#{age},#{gender},#{email}); </insert > </mapper >
测试类 SpecialSQLMapperTest.java 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 package com.zzmr.mybatis.test;import com.zzmr.mybatis.mapper.SpecialSQLMapper;import com.zzmr.mybatis.pojo.User;import com.zzmr.mybatis.utils.SqlSessionUtil;import org.apache.ibatis.session.SqlSession;import org.junit.Test;import java.util.List;public class SpecialSQLMapperTest { @Test public void testSpecialSQLMapper () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); SpecialSQLMapper mapper = sqlSession.getMapper(SpecialSQLMapper.class); List<User> users = mapper.getUserByLike("zz" ); for (User user : users) { System.out.println(user); } } @Test public void testDeleteMoreUser () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); SpecialSQLMapper mapper = sqlSession.getMapper(SpecialSQLMapper.class); mapper.deleteMoreUser("12,15" ); } @Test public void testGetUserList () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); SpecialSQLMapper mapper = sqlSession.getMapper(SpecialSQLMapper.class); List<User> t_user = mapper.getUserList("t_user" ); t_user.forEach(System.out::println); } @Test public void testInsertUser () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); SpecialSQLMapper mapper = sqlSession.getMapper(SpecialSQLMapper.class); User user = new User (null ,"xiaom11in2312g" ,"9121" ,23 ,"男" ,"231@13.com" ); mapper.insertUser(user); System.out.println(user); } }
搭建MyBatis框架 将下划线映射为驼峰解决Java属性和MySql数据库中的字段名不一致的情况
1 2 3 4 <settings > <setting name ="mapUnderscoreToCamelCase" value ="true" /> </settings >
自定义映射 一堆代码即将来袭
Emp.java 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 package com.zzmr.mybatis.pojo;public class Emp { private Integer empId; private String empName; private Integer age; private String gender; private Dept dept; @Override public String toString () { return "Emp{" + "empId=" + empId + ", empName='" + empName + '\'' + ", age=" + age + ", gender='" + gender + '\'' + ", dept=" + dept + '}' ; } public Dept getDept () { return dept; } public void setDept (Dept dept) { this .dept = dept; } public Integer getEmpId () { return empId; } public void setEmpId (Integer empId) { this .empId = empId; } public String getEmpName () { return empName; } public void setEmpName (String empName) { this .empName = empName; } public Integer getAge () { return age; } public void setAge (Integer age) { this .age = age; } public String getGender () { return gender; } public void setGender (String gender) { this .gender = gender; } public Emp () { } public Emp (Integer empId, String empName, Integer age, String gender) { this .empId = empId; this .empName = empName; this .age = age; this .gender = gender; } }
Dept.java 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 package com.zzmr.mybatis.pojo;import java.util.List;public class Dept { private Integer deptId; private String deptName; private List<Emp> emps; @Override public String toString () { return "Dept{" + "deptId=" + deptId + ", deptName='" + deptName + '\'' + ", emps=" + emps + '}' ; } public List<Emp> getEmps () { return emps; } public void setEmps (List<Emp> emps) { this .emps = emps; } public Integer getDeptId () { return deptId; } public void setDeptId (Integer deptId) { this .deptId = deptId; } public String getDeptName () { return deptName; } public void setDeptName (String deptName) { this .deptName = deptName; } public Dept () { } public Dept (Integer deptId, String deptName) { this .deptId = deptId; this .deptName = deptName; } }
EmpMapper.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace ="com.zzmr.mybatis.mapper.EmpMapper" > <resultMap id ="empResultMap" type ="Emp" > <id column ="emp_id" property ="empId" > </id > <result column ="emp_name" property ="empName" > </result > <result column ="age" property ="age" > </result > <result column ="gender" property ="gender" > </result > </resultMap > <select id ="getEmpByEmpId" resultMap ="empResultMap" > select * from t_emp where emp_id = #{empId}; </select > <select id ="getEmpByEmpIdOld" resultType ="Emp" > select * from t_emp where emp_id = #{empId}; </select > <resultMap id ="empAndDeptResultMapOne" type ="Emp" > <id column ="emp_id" property ="empId" > </id > <result column ="emp_name" property ="empName" > </result > <result column ="age" property ="age" > </result > <result column ="gender" property ="gender" > </result > <result column ="dept_id" property ="dept.deptId" > </result > <result column ="dept_name" property ="dept.deptName" > </result > </resultMap > <resultMap id ="empAndDeptResultMap" type ="Emp" > <id column ="emp_id" property ="empId" > </id > <result column ="emp_name" property ="empName" > </result > <result column ="age" property ="age" > </result > <result column ="gender" property ="gender" > </result > <association property ="dept" javaType ="Dept" > <id column ="dept_id" property ="deptId" > </id > <result column ="dept_name" property ="deptName" > </result > </association > </resultMap > <select id ="getEmpAndDeptByEmpId" resultMap ="empAndDeptResultMap" > select t_emp.*,t_dept.* from t_emp left join t_dept on t_emp.dept_id = t_dept.dept_id WHERE t_emp.emp_id = #{empId}; </select > <resultMap id ="empAndDeptByStepResultMap" type ="Emp" > <id column ="emp_id" property ="empId" > </id > <result column ="emp_name" property ="empName" > </result > <result column ="age" property ="age" > </result > <result column ="gender" property ="gender" > </result > <association property ="dept" fetchType ="eager" select ="com.zzmr.mybatis.mapper.DeptMapper.getEmpAndDeptByStepTwo" column ="dept_id" > </association > </resultMap > <select id ="getEmpAndDeptByStepOne" resultMap ="empAndDeptByStepResultMap" > select * from t_emp where emp_id = #{empId}; </select > <select id ="getDeptAndEmpByStepTwo" resultType ="Emp" > select * from t_emp where dept_id = #{deptId}; </select > </mapper >
DeptMapper.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace ="com.zzmr.mybatis.mapper.EmpMapper" > <resultMap id ="empResultMap" type ="Emp" > <id column ="emp_id" property ="empId" > </id > <result column ="emp_name" property ="empName" > </result > <result column ="age" property ="age" > </result > <result column ="gender" property ="gender" > </result > </resultMap > <select id ="getEmpByEmpId" resultMap ="empResultMap" > select * from t_emp where emp_id = #{empId}; </select > <select id ="getEmpByEmpIdOld" resultType ="Emp" > select * from t_emp where emp_id = #{empId}; </select > <resultMap id ="empAndDeptResultMapOne" type ="Emp" > <id column ="emp_id" property ="empId" > </id > <result column ="emp_name" property ="empName" > </result > <result column ="age" property ="age" > </result > <result column ="gender" property ="gender" > </result > <result column ="dept_id" property ="dept.deptId" > </result > <result column ="dept_name" property ="dept.deptName" > </result > </resultMap > <resultMap id ="empAndDeptResultMap" type ="Emp" > <id column ="emp_id" property ="empId" > </id > <result column ="emp_name" property ="empName" > </result > <result column ="age" property ="age" > </result > <result column ="gender" property ="gender" > </result > <association property ="dept" javaType ="Dept" > <id column ="dept_id" property ="deptId" > </id > <result column ="dept_name" property ="deptName" > </result > </association > </resultMap > <select id ="getEmpAndDeptByEmpId" resultMap ="empAndDeptResultMap" > select t_emp.*,t_dept.* from t_emp left join t_dept on t_emp.dept_id = t_dept.dept_id WHERE t_emp.emp_id = #{empId}; </select > <resultMap id ="empAndDeptByStepResultMap" type ="Emp" > <id column ="emp_id" property ="empId" > </id > <result column ="emp_name" property ="empName" > </result > <result column ="age" property ="age" > </result > <result column ="gender" property ="gender" > </result > <association property ="dept" fetchType ="eager" select ="com.zzmr.mybatis.mapper.DeptMapper.getEmpAndDeptByStepTwo" column ="dept_id" > </association > </resultMap > <select id ="getEmpAndDeptByStepOne" resultMap ="empAndDeptByStepResultMap" > select * from t_emp where emp_id = #{empId}; </select > <select id ="getDeptAndEmpByStepTwo" resultType ="Emp" > select * from t_emp where dept_id = #{deptId}; </select > </mapper >
DeptMapper.java 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 package com.zzmr.mybatis.mapper;import com.zzmr.mybatis.pojo.Dept;import org.apache.ibatis.annotations.Param;public interface DeptMapper { Dept getEmpAndDeptByStepTwo (@Param("deptId") Integer deptId) ; Dept getDeptAndEmpByDeptId (@Param("deptId") Integer deptId) ; Dept getDeptAndEmpByStepOne (@Param("deptId") Integer deptId) ; }
EmpMapper.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 package com.zzmr.mybatis.mapper;import com.zzmr.mybatis.pojo.Emp;import org.apache.ibatis.annotations.Param;import java.util.List;public interface EmpMapper { Emp getEmpByEmpId (@Param("empId") Integer empId) ; Emp getEmpAndDeptByEmpId (@Param("empId") Integer empId) ; Emp getEmpAndDeptByStepOne (@Param("empId") Integer empId) ; List<Emp> getDeptAndEmpByStepTwo (@Param("deptId") Integer deptId) ; }
测试 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 import com.zzmr.mybatis.mapper.DeptMapper;import com.zzmr.mybatis.mapper.EmpMapper;import com.zzmr.mybatis.pojo.Dept;import com.zzmr.mybatis.pojo.Emp;import com.zzmr.mybatis.utils.SqlSessionUtil;import org.apache.ibatis.session.SqlSession;import org.junit.Test;public class ResultMapTest { @Test public void testGetEmpByEmpId () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); EmpMapper mapper = sqlSession.getMapper(EmpMapper.class); Emp emp = mapper.getEmpByEmpId(1 ); System.out.println(emp); } @Test public void testGetEmpAndDeptByEmpId () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); EmpMapper mapper = sqlSession.getMapper(EmpMapper.class); Emp emp = mapper.getEmpAndDeptByEmpId(1 ); System.out.println(emp); } @Test public void testGetEmpAndDeptByStep () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); EmpMapper mapper = sqlSession.getMapper(EmpMapper.class); Emp emp = mapper.getEmpAndDeptByStepOne(2 ); System.out.println(emp.getEmpName()); } @Test public void testGetDeptAndEmpByDeptId () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); DeptMapper mapper = sqlSession.getMapper(DeptMapper.class); Dept dept = mapper.getDeptAndEmpByDeptId(1 ); System.out.println(dept); } @Test public void testGetDeptAndEmpByStep () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); DeptMapper mapper = sqlSession.getMapper(DeptMapper.class); Dept dept = mapper.getDeptAndEmpByStepOne(1 ); System.out.println(dept.getDeptName()); } }
分步查询的优点：可以实现延迟加载
1 2 3 4 <setting name ="lazyLoadingEnabled" value ="true" /> <setting name ="aggressiveLazyLoading" value ="false" />
动态SQL MyBatis框架的动态SQL技术是一种根据特定条件动态拼装SQL语句的功能,它存在的意义是为了解决拼接SQL语句字符串时的痛点问题
基本标签 if
1 2 3 4 5 6 7 8 9 10 11 12 13 <select id ="getEmpByCondition" resultType ="Emp" > select * from t_emp where <if test ="empName != null and empName != ''" > emp_name = #{empName} </if > <if test ="age != null and age != ''" > and age = #{age} </if > <if test ="gender != null and gender != ''" > and gender = #{gender} </if > </select >
这种写法是有问题的,当empName是空时,后台执行的SQL语句就成了:
1 select * from t_emp where and age = ? and gender = ?
很显然,sql语法是有问题的,where后面不能直接跟and
1 Emp emp = new Emp (null , "" , null , "" );
此时就会发生:
1 select * from t_emp where
没错,多了一个where,因为where写死在上面了,所以还需要改进:
方法一:
1 2 3 4 5 6 7 8 9 10 11 12 13 <select id ="getEmpByCondition" resultType ="Emp" > select * from t_emp where 1=1 <if test ="empName != null and empName != ''" > and emp_name = #{empName} </if > <if test ="age != null and age != ''" > and age = #{age} </if > <if test ="gender != null and gender != ''" > and gender = #{gender} </if > </select >
此时在where后面加上一个恒成立的表达式1=1后面每个if都加上and,就能解决上面出现的问题,因为当下面的语句都不执行时,where1=1会让sql继续正确执行,而当下面第一个条件为空时,因为where后面已经有一个条件了,所以直接跟第二个条件的and是没问题的,也不会影响SQL查询的结果.
方法二:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 <select id ="getEmpByCondition" resultType ="Emp" > select * from t_emp <where > <if test ="empName != null and empName != ''" > emp_name = #{empName} </if > <if test ="age != null and age != ''" > and age = #{age} </if > <if test ="gender != null and gender != ''" > and gender = #{gender} </if > </where > </select >
where标签的作用:
会给下面的if自动生成where关键字
可以将多余的and去掉,比如第一个条件为空时,可以将第二个条件的and给去掉
如果下方的if都不成立,此时不会生成where关键字
注意,where标签不能去掉条件后的and同样可以解决上面出现的问题
但是如果将条件前的and换到条件后
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 <select id ="getEmpByCondition" resultType ="Emp" > select * from t_emp <trim prefix ="where" suffixOverrides ="and" > <if test ="empName != null and empName != ''" > emp_name = #{empName} and </if > <if test ="age != null and age != ''" > age = #{age} and </if > <if test ="gender != null and gender != ''" > gender = #{gender} </if > </trim > </select >
这时就要使用trim标签了,trim标签可以在条件前添加关键字,在条件后删除关键字,比如上面就是使用trim来实现在条件前添加where ,以及在条件后删除多余的and
choose,when,otherwise标签
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 <select id ="getEmpByChoose" resultType ="Emp" > select * from t_emp <where > <choose > <when test ="empName!=null and empName != ''" > emp_name = #{empName} </when > <when test ="age!=null and age!=''" > age = #{age} </when > <when test ="gender!=null and gender != ''" > gender = #{gender} </when > </choose > </where > </select >
这个标签用的不多,后面逆向工程可能会涉及到
forEach
实现批量添加的操作：
1 2 3 4 5 6 7 <insert id ="insertMoreEmp" > insert into t_emp values <foreach collection ="emps" item ="emp" separator ="," > (null,#{emp.empName},#{emp.age},#{emp.gender},null) </foreach > </insert >
1 2 3 4 5 6 7 8 9 10 @Test public void testInsertMoreEmp () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); DynamicSQLMapper mapper = sqlSession.getMapper(DynamicSQLMapper.class); Emp emp1 = new Emp (null , "zzmr1" ,20 , "男" ); Emp emp2 = new Emp (null , "zzmr2" ,20 , "女" ); Emp emp3 = new Emp (null , "zzmr3" ,20 , "女" ); List<Emp> emps = Arrays.asList(emp1, emp2, emp3); mapper.insertMoreEmp(emps); }
实现批量删除的操作：
1 2 3 4 5 6 7 8 9 10 11 <delete id ="deleteMoreEmp" > delete from t_emp where <foreach collection ="empIds" item ="empId" separator ="or" > emp_id = #{empId} </foreach > </delete >
1 2 3 4 5 6 7 @Test public void testDeleteMoreEmp () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); DynamicSQLMapper mapper = sqlSession.getMapper(DynamicSQLMapper.class); Integer[] emps = new Integer []{3 ,4 }; mapper.deleteMoreEmp(emps); }
这个还是挺好用的
1 2 3 4 5 6 5 foreach collection 设置循环的数组或集合 item 用一个字符串表示数组或集合中的每一个数据 separator 设置每次循环的数据之间的分隔符 open 循环的所有内容以什么开始 close 循环的所有内容以什么结束
sql 标签
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 <sql id ="empColumns" > emp_id,emp_name,age,gender,dept_id </sql > <select id ="getEmpByCondition" resultType ="Emp" > select <include refid ="empColumns" > </include > from t_emp <trim prefix ="where" suffixOverrides ="and" > <if test ="empName != null and empName != ''" > emp_name = #{empName} and </if > <if test ="age != null and age != ''" > age = #{age} and </if > <if test ="gender != null and gender != ''" > gender = #{gender} </if > </trim > </select >
创建一个sql标签,里面放上字段,一般是一个表的字段,在用到的时候直接用include引用,避免使用*的情况,因为 星号会影响效率
动态SQL总结 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace ="com.zzmr.mybatis.mapper.DynamicSQLMapper" > <sql id ="empColumns" > emp_id,emp_name,age,gender,dept_id </sql > <select id ="getEmpByCondition" resultType ="Emp" > select <include refid ="empColumns" > </include > from t_emp <trim prefix ="where" suffixOverrides ="and" > <if test ="empName != null and empName != ''" > emp_name = #{empName} and </if > <if test ="age != null and age != ''" > age = #{age} and </if > <if test ="gender != null and gender != ''" > gender = #{gender} </if > </trim > </select > <select id ="getEmpByConditionTwo" resultType ="Emp" > select * from t_emp <where > <if test ="empName != null and empName != ''" > emp_name = #{empName} </if > <if test ="age != null and age != ''" > and age = #{age} </if > <if test ="gender != null and gender != ''" > and gender = #{gender} </if > </where > </select > <select id ="getEmpByConditionOne" resultType ="Emp" > select * from t_emp where 1=1 <if test ="empName != null and empName != ''" > and emp_name = #{empName} </if > <if test ="age != null and age != ''" > and age = #{age} </if > <if test ="gender != null and gender != ''" > and gender = #{gender} </if > </select > <select id ="getEmpByChoose" resultType ="Emp" > select * from t_emp <where > <choose > <when test ="empName!=null and empName != ''" > emp_name = #{empName} </when > <when test ="age!=null and age!=''" > age = #{age} </when > <when test ="gender!=null and gender != ''" > gender = #{gender} </when > </choose > </where > </select > <insert id ="insertMoreEmp" > insert into t_emp values <foreach collection ="emps" item ="emp" separator ="," > (null,#{emp.empName},#{emp.age},#{emp.gender},null) </foreach > </insert > <delete id ="deleteMoreEmp" > delete from t_emp where <foreach collection ="empIds" item ="empId" separator ="or" > emp_id = #{empId} </foreach > </delete > </mapper >
MyBatis的缓存 MyBatis的一级缓存 一节缓存是SqlSession级别的,通过同一个SqlSession查询的数据会被缓存,下次查询相同的数据,就会从缓存中直接获取,不会从数据库重新访问
不同的SqlSession对应的不同的一级缓存
同一个SqlSession但是查询条件不同
同一个SqlSession两次查询期间执行了任何一次增删改操作
同一个SqlSession两次查询期间手动清理了缓存
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 @Test public void testGetEmpById () { SqlSession sqlSession1 = SqlSessionUtil.getSqlSession(); CacheMapper mapper1 = sqlSession1.getMapper(CacheMapper.class); Emp emp1 = mapper1.getEmpById(1 ); System.out.println(emp1); sqlSession1.clearCache(); Emp emp2 = mapper1.getEmpById(1 ); System.out.println(emp2); }
MyBatis的二级缓存 二级缓存是SqlSessionFactory级别,通过同一个SqlSessionfactory创建的SqlSession查询的结果会被缓存,此后若再次执行相同的查询语句,结果就会从缓存中获取
在核心配置文件中,着这全局配置属性cacheEnabled=”true” 默认为true,不需要设置
在映射文件中设置 <cache/>
二级缓存必须在SqlSession关闭或提交之后有效
查询的数据所转换的实体类类型必须实现序列化的接口
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 @Test public void testCache () throws IOException { InputStream is = Resources.getResourceAsStream("mybatis-config.xml" ); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder ().build(is); SqlSession sqlSession1 = sqlSessionFactory.openSession(true ); CacheMapper mapper1 = sqlSession1.getMapper(CacheMapper.class); Emp emp1 = mapper1.getEmpById(1 ); System.out.println(emp1); sqlSession1.close(); SqlSession sqlSession2 = sqlSessionFactory.openSession(true ); CacheMapper mapper2 = sqlSession2.getMapper(CacheMapper.class); Emp emp2 = mapper2.getEmpById(1 ); System.out.println(emp2); sqlSession2.close(); }
二级缓存的相关配置
MyBatis缓存查询的顺序
整合第三方缓存EHCache 需要添加依赖:
MyBatis逆向工程 正向工程:先创建Java实体类,由框架负责根据实体类生成数据库表,Hibernate是支持正向工程的
Java实体类
Mapper接口
Mapper映射文件
卧槽
配置文件写一哈,以后用到了直接拷贝:
generatorConfig.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN" "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd" > <generatorConfiguration > <context id ="DB2Tables" targetRuntime ="MyBatis3" > <jdbcConnection driverClass ="com.mysql.cj.jdbc.Driver" connectionURL ="jdbc:mysql://localhost:3306/ssm? serverTimezone=UTC" userId ="root" password ="010203" > </jdbcConnection > <javaModelGenerator targetPackage ="com.zzmr.mybatis.pojo" targetProject =".\src\main\java" > <property name ="enableSubPackages" value ="true" /> <property name ="trimStrings" value ="true" /> </javaModelGenerator > <sqlMapGenerator targetPackage ="com.zzmr.mybatis.mapper" targetProject =".\src\main\resources" > <property name ="enableSubPackages" value ="true" /> </sqlMapGenerator > <javaClientGenerator type ="XMLMAPPER" targetPackage ="com.zzmr.mybatis.mapper" targetProject =".\src\main\java" > <property name ="enableSubPackages" value ="true" /> </javaClientGenerator > <table tableName ="t_emp" domainObjectName ="Emp" /> <table tableName ="t_dept" domainObjectName ="Dept" /> </context > </generatorConfiguration >
pom.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 <?xml version="1.0" encoding="UTF-8" ?> <project xmlns ="http://maven.apache.org/POM/4.0.0" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" > <modelVersion > 4.0.0</modelVersion > <groupId > com.zzmr.mybatis</groupId > <artifactId > mybatis_mbg</artifactId > <version > 1.0-SNAPSHOT</version > <packaging > jar</packaging > <properties > <maven.compiler.source > 8</maven.compiler.source > <maven.compiler.target > 8</maven.compiler.target > <project.build.sourceEncoding > UTF-8</project.build.sourceEncoding > </properties > <dependencies > <dependency > <groupId > org.mybatis</groupId > <artifactId > mybatis</artifactId > <version > 3.5.7</version > </dependency > <dependency > <groupId > junit</groupId > <artifactId > junit</artifactId > <version > 4.12</version > <scope > test</scope > </dependency > <dependency > <groupId > log4j</groupId > <artifactId > log4j</artifactId > <version > 1.2.17</version > </dependency > <dependency > <groupId > mysql</groupId > <artifactId > mysql-connector-java</artifactId > <version > 8.0.16</version > </dependency > </dependencies > <build > <plugins > <plugin > <groupId > org.mybatis.generator</groupId > <artifactId > mybatis-generator-maven-plugin</artifactId > <version > 1.3.0</version > <dependencies > <dependency > <groupId > org.mybatis.generator</groupId > <artifactId > mybatis-generator-core</artifactId > <version > 1.3.2</version > </dependency > <dependency > <groupId > mysql</groupId > <artifactId > mysql-connector-java</artifactId > <version > 8.0.16</version > </dependency > </dependencies > </plugin > </plugins > </build > </project >
然后是测试,简单测试一下,对于单表来说,这个插件已经完成了所有的增上改查的功能了
MBGTest.java 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 package com.zzmr.mybatis.test;import com.zzmr.mybatis.mapper.EmpMapper;import com.zzmr.mybatis.pojo.Emp;import com.zzmr.mybatis.pojo.EmpExample;import com.zzmr.mybatis.utils.SqlSessionUtil;import org.apache.ibatis.session.SqlSession;import org.junit.Test;import java.util.List;public class MBGTest { @Test public void testMBG () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); EmpMapper mapper = sqlSession.getMapper(EmpMapper.class); Emp emp = new Emp (8 ,"灼灼某人1" ,null ,"男" ); mapper.updateByPrimaryKeySelective(emp); } }
分页插件 分页的基本操作:pageSize (pageNum-1) limit 8,4
分页插件使用步骤:
添加依赖
1 2 3 4 5 <dependency > <groupId > com.github.pagehelper</groupId > <artifactId > pagehelper</artifactId > <version > 5.2.0</version > </dependency >
配置分页插件
1 2 3 <plugins > <plugin interceptor ="com.github.pagehelper.PageInterceptor" > </plugin > </plugins >
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 package com.zzmr.mybatis.test;import com.github.pagehelper.Page;import com.github.pagehelper.PageHelper;import com.github.pagehelper.PageInfo;import com.zzmr.mybatis.mapper.EmpMapper;import com.zzmr.mybatis.pojo.Emp;import com.zzmr.mybatis.utils.SqlSessionUtil;import org.apache.ibatis.session.SqlSession;import org.junit.Test;import java.util.List;public class PageTest { @Test public void testPage () { SqlSession sqlSession = SqlSessionUtil.getSqlSession(); EmpMapper mapper = sqlSession.getMapper(EmpMapper.class); Page<Object> page = PageHelper.startPage(5 , 4 ); List<Emp> emps = mapper.selectByExample(null ); PageInfo<Emp> pageInfo = new PageInfo <>(emps, 5 ); emps.forEach(System.out::println); System.out.println(pageInfo); } }
太几把好用了!!!
Spring Spring官网地址:https://spring.io/
Spring家族 项目列表:https://spring.io/projects
Spring Framework
IOC容器 IOC思想： Inversion of Control 翻译过来就是反转控制
获取资源的传统方式主动 的从容器中获取所需要的此资源,在这样的模式下开发人员人员往往需要直到在具体容器中特定资源的获取方式,增加了学习成本,同时降低了开发效率
反转控制方式获取资源被动 形式
DI
IOC容器在Spring中的实现 Spring的IOC容器就是IOC思想的一个落地的产品实现,IOC容器中管理的组件也叫bean,在创建之前,首先需要创建IOC容器,Spring提供了IOC容器的两种实现方式
BeanFactroy
ApplicationContext
ApplicationContext的主要实现类:
添加依赖:pom.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 <dependencies > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-context</artifactId > <version > 5.3.1</version > </dependency > <dependency > <groupId > junit</groupId > <artifactId > junit</artifactId > <version > 4.12</version > <scope > test</scope > </dependency > </dependencies >
继续XML管理bean applicationContext.xml Spring的配置文件
1 2 3 4 5 6 7 8 9 10 11 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd" > <bean id ="helloworld" class ="com.zzmr.spring.pojo.HelloWorld" > </bean > </beans >
测试类:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 package com.zzmr.spring.test;import com.zzmr.spring.pojo.HelloWorld;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class HelloWorldTest { @Test public void testHelloWorld () { ApplicationContext ioc = new ClassPathXmlApplicationContext ("applicationContext.xml" ); HelloWorld helloworld = (HelloWorld) ioc.getBean("helloworld" ); helloworld.sayHello(); } }
注意: 当根据类型获取bean时,要求IOC容器中指定类型的bean有且只能有一个
如果组件类实现了接口,根据接口类型可以获取bean,前提是bean唯一
但如果一个接口有多个实现类,这些实现类都配置了bean,根据接口类型就不能获取bean了,因为bean不唯一
根据类型来获取bean时,在满足bean唯一性的前提下,其实只是看:对象instanceof指定的类型的返回结果,只要返回的是true,就可以认定为和类型匹配,能够获取到
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 package com.zzmr.spring.test;import com.zzmr.spring.pojo.Student;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class IOCByXMLTest { @Test public void testIOC () { ApplicationContext ioc = new ClassPathXmlApplicationContext ("spring-ioc.xml" ); Student studentOne = ioc.getBean("studentOne" , Student.class); System.out.println(studentOne); } }
依赖注入之setter注入 怎么写？
1 2 3 4 5 6 7 8 9 10 <bean id ="studentTwo" class ="com.zzmr.spring.pojo.Student" > <property name ="sid" value ="1001" > </property > <property name ="sname" value ="张三" > </property > <property name ="age" value ="23" > </property > <property name ="gender" value ="男" > </property > </bean >
1 2 3 4 5 6 7 @Test public void testDI () { ApplicationContext ioc = new ClassPathXmlApplicationContext ("spring-ioc.xml" ); Student student = ioc.getBean("studentTwo" , Student.class); System.out.println(student); }
也不难,嗯
依赖注入之构造器注入 1 2 3 4 5 6 <bean id ="studentThree" class ="com.zzmr.spring.pojo.Student" > <constructor-arg value ="1002" > </constructor-arg > <constructor-arg value ="李四" > </constructor-arg > <constructor-arg value ="女" > </constructor-arg > <constructor-arg value ="24" name ="score" > </constructor-arg > </bean >
1 2 3 4 5 6 7 @Test public void testDI () { ApplicationContext ioc = new ClassPathXmlApplicationContext ("spring-ioc.xml" ); Student student = ioc.getBean("studentThree" , Student.class); System.out.println(student); }
这个用的不多,后面用setter会比较多
特殊值处理: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 <bean id ="studentFour" class ="com.zzmr.spring.pojo.Student" > <property name ="sid" value ="1003" > </property > <property name ="sname" > <value > <![CDATA[<王五>]]></value > </property > <property name ="gender" > <null /> </property > </bean >
CDATA节自动生成快捷键: 大写CD,回车,注意:CDATA是xml中的一个特殊的标签,不能写在属性里面
为类类型的属性值赋值
1 2 3 4 5 6 7 8 9 10 11 12 <bean id ="studentFive" class ="com.zzmr.spring.pojo.Student" > <property name ="sid" value ="1004" > </property > <property name ="sname" value ="赵六" > </property > <property name ="age" value ="14" > </property > <property name ="gender" value ="男" > </property > <property name ="clazz" ref ="clazzOne" > </property > </bean > <bean id ="clazzOne" class ="com.zzmr.spring.pojo.Clazz" > <property name ="cid" value ="1111" > </property > <property name ="cname" value ="三年二班" > </property > </bean >
使用内部bean
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 <bean id ="studentFive" class ="com.zzmr.spring.pojo.Student" > <property name ="sid" value ="1004" > </property > <property name ="sname" value ="赵六" > </property > <property name ="age" value ="14" > </property > <property name ="gender" value ="男" > </property > <property name ="clazz" > <bean id ="clazzInner" class ="com.zzmr.spring.pojo.Clazz" > <property name ="cid" value ="2222" > </property > <property name ="cname" value ="灼灼某人版" > </property > </bean > </property > </bean > <bean id ="clazzOne" class ="com.zzmr.spring.pojo.Clazz" > <property name ="cid" value ="1111" > </property > <property name ="cname" value ="三年二班" > </property > </bean >
内部bean只能在当前bean的内部使用，不能直接通过ioc获取
好多啊:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xmlns:util ="http://www.springframework.org/schema/util" xmlns:utils ="http://www.springframework.org/schema/util" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/util https://www.springframework.org/schema/util/spring-util.xsd" > <bean id ="studentOne" class ="com.zzmr.spring.pojo.Student" > </bean > <bean id ="studentTwo" class ="com.zzmr.spring.pojo.Student" > <property name ="sid" value ="1001" > </property > <property name ="sname" value ="张三" > </property > <property name ="age" value ="23" > </property > <property name ="gender" value ="男" > </property > </bean > <bean id ="studentThree" class ="com.zzmr.spring.pojo.Student" > <constructor-arg value ="1002" > </constructor-arg > <constructor-arg value ="李四" > </constructor-arg > <constructor-arg value ="女" > </constructor-arg > <constructor-arg value ="24" name ="score" > </constructor-arg > </bean > <bean id ="studentFour" class ="com.zzmr.spring.pojo.Student" > <property name ="sid" value ="1003" > </property > <property name ="sname" > <value > <![CDATA[<王五>]]></value > </property > <property name ="gender" > <null /> </property > </bean > <bean id ="studentFive" class ="com.zzmr.spring.pojo.Student" > <property name ="sid" value ="1004" > </property > <property name ="sname" value ="赵六" > </property > <property name ="age" value ="14" > </property > <property name ="gender" value ="男" > </property > <property name ="clazz" > <bean id ="clazzInner" class ="com.zzmr.spring.pojo.Clazz" > <property name ="cid" value ="2222" > </property > <property name ="cname" value ="灼灼某人版" > </property > </bean > </property > <property name ="hobby" > <array > <value > 抽烟</value > <value > 喝酒</value > <value > 烫头</value > </array > </property > <property name ="teacherMap" ref ="teacherMap" > </property > </bean > <bean id ="clazzOne" class ="com.zzmr.spring.pojo.Clazz" > <property name ="cid" value ="1111" > </property > <property name ="cname" value ="三年二班" > </property > <property name ="students" ref ="studentList" > </property > </bean > <bean id ="teacherOne" class ="com.zzmr.spring.pojo.Teacher" > <property name ="tid" value ="10084" > </property > <property name ="tname" value ="10085" > </property > </bean > <bean id ="teacherTwo" class ="com.zzmr.spring.pojo.Teacher" > <property name ="tid" value ="100844" > </property > <property name ="tname" value ="100855" > </property > </bean > <util:list id ="studentList" > <ref bean ="studentOne" > </ref > <ref bean ="studentTwo" > </ref > <ref bean ="studentThree" > </ref > </util:list > <utils:map id ="teacherMap" > <entry key ="10084" value-ref ="teacherOne" > </entry > <entry key ="100844" value-ref ="teacherTwo" > </entry > </utils:map > <bean id ="studentSix" class ="com.zzmr.spring.pojo.Student" p:sid ="1005" p:sname ="小明" p:teacherMap-ref ="teacherMap" > </bean > </beans >
Spring管理数据源 Spring管理数据源和引入外部属性文件
引入数据库连接组件
1 2 3 4 jdbc.driver=com.mysql.cj.jdbc.Driver jdbc.url=jdbc:mysql: jdbc.username=root jdbc.password=010203
1 2 3 4 5 6 7 8 9 <context:property-placeholder location ="jdbc.properties" > </context:property-placeholder > <bean id ="dataSource" class ="com.alibaba.druid.pool.DruidDataSource" > <property name ="driverClassName" value ="${jdbc.driver}" > </property > <property name ="url" value ="${jdbc.url}" > </property > <property name ="username" value ="${jdbc.username}" > </property > <property name ="password" value ="${jdbc.password}" > </property > </bean >
bean的作用域 在Spring中可以通过配置bean标签的scope属性来指定bean的作用域范围,各取值含义参见下表
1 2 3 4 5 6 7 8 9 10 11 12 <bean id ="student" class ="com.zzmr.spring.pojo.Student" scope ="prototype" > <property name ="sid" value ="2009124101" > </property > <property name ="sname" value ="杨晋" > </property > </bean >
1 2 3 4 5 6 7 8 @Test public void testScope () { ApplicationContext ioc = new ClassPathXmlApplicationContext ("spring-scope.xml" ); Student student1 = ioc.getBean(Student.class); Student student2 = ioc.getBean(Student.class); System.out.println(student1==student2); }
bean的生命周期 具体的生命周期过程
bean对象创建(调用无参构造器)
给bean对象设置属性
bean对象初始化之前操作(由bean的后置处理器负责)
bean对象初始化(需要在配置bean时指定初始化方法)
bean对象初始化之后操作(由bean的后置处理器负责)
bean对象就绪可以使用
bean对象销毁(需在配置bean时指定销毁方法)
IOC容器关闭
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 public class LifeCycleTest { @Test public void test () { ConfigurableApplicationContext ioc = new ClassPathXmlApplicationContext ("spring-lifecycle.xml" ); User user = ioc.getBean(User.class); System.out.println(user); ioc.close(); }
1 2 3 4 5 6 <bean id ="user" class ="com.zzmr.spring.pojo.User" init-method ="initMethod" destroy-method ="destroyMethod" > <property name ="id" value ="1" > </property > <property name ="username" value ="admin" > </property > <property name ="password" value ="010203" > </property > <property name ="age" value ="20" > </property > </bean >
其中User.java中有方法：
1 2 3 4 5 6 public void initMethod () { System.out.println("生命周期3：初始化" ); } public void destroyMethod () { System.out.println("生命周期4：销毁" ); }
了解一下：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 package com.zzmr.spring.test;import com.zzmr.spring.pojo.User;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.ConfigurableApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class LifeCycleTest { @Test public void test () { ConfigurableApplicationContext ioc = new ClassPathXmlApplicationContext ("spring-lifecycle.xml" ); User user = ioc.getBean(User.class); System.out.println(user); ioc.close(); } }
将后置处理器配置到IOC容器中
1 <bean id ="myBeanPostProcessor" class ="com.zzmr.spring.process.MyBeanPostProcessor" > </bean >
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 package com.zzmr.spring.process;import org.springframework.beans.BeansException;import org.springframework.beans.factory.config.BeanPostProcessor;public class MyBeanPostProcessor implements BeanPostProcessor { @Override public Object postProcessBeforeInitialization (Object bean, String beanName) throws BeansException { System.out.println("MyBeanPostProcessor---->后置处理器的postProcessBeforeInitialization" ); return bean; } @Override public Object postProcessAfterInitialization (Object bean, String beanName) throws BeansException { System.out.println("MyBeanPostProcessor---->后置处理器的postProcessAfterInitialization" ); return bean; } }
FactoryBean FactoryBean是Spring提供的一种整合第三方框架的常用机制,和普通的bean不同,配置一个FactoryBean类型的bean,在获取bean的时候得到的并不是class属性中配置的这个类的对象,而是getObject()方法的返回值,通过这种机制,Spring可以帮我们把复杂组件创建的详细过程和繁琐细节都屏蔽起来,只把最简洁的使用界面展示给我们.将来整合MyBatis时,Spring就是通过FactoryBean机制来我们创建SqlSessionFactroy对象的
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 package com.zzmr.spring.factory;import com.zzmr.spring.pojo.User;import org.springframework.beans.factory.FactoryBean;public class UserFactoryBean implements FactoryBean <User> { @Override public User getObject () throws Exception { return new User (); } @Override public Class<?> getObjectType() { return User.class; } }
1 <bean class ="com.zzmr.spring.factory.UserFactoryBean" />
1 2 3 4 5 6 @Test public void testFactoryBean () { ApplicationContext ioc = new ClassPathXmlApplicationContext ("spring-factory.xml" ); User user = ioc.getBean(User.class); System.out.println(user); }
基于xml的自动装配 自动装配:根据指定的策略,在IOC容器中匹配某一个bean,自动为指定的bean中所依赖的类类型或接口属性赋值
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 package com.zzmr.spring.test;import com.zzmr.spring.controller.UserController;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class AutowireByXMLTest { @Test public void testAutowire () { ApplicationContext ioc = new ClassPathXmlApplicationContext ("spring-autowire-xml.xml" ); UserController userController = ioc.getBean(UserController.class); userController.saveUser(); } }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd" > <bean id ="userController" class ="com.zzmr.spring.controller.UserController" autowire ="byName" > </bean > <bean id ="userService" class ="com.zzmr.spring.service.impl.UserServiceImpl" autowire ="byName" > </bean > <bean id ="userDao" class ="com.zzmr.spring.dao.impl.UserDaoImpl" > </bean > </beans >
但是后期开发用的还是基于注解管理bean也是挺多的,同样很重要
基于注解管理bean 注解
扫描 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xmlns:context ="http://www.springframework.org/schema/context" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd" > <context:component-scan base-package ="com.zzmr.spring" > </context:component-scan > </beans >
测试：
1 2 3 4 5 6 7 8 9 10 11 @Test public void test () { ApplicationContext ioc = new ClassPathXmlApplicationContext ("spring-ioc-annotation.xml" ); UserController userController = ioc.getBean(UserController.class); System.out.println(userController); UserService userService = ioc.getBean(UserService.class); System.out.println(userService); UserDao userDao = ioc.getBean(UserDao.class); System.out.println(userDao); }
了解最重要,最常用的就是给属性直接加注解
基于注解的自动装配 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 package com.zzmr.spring.test;import com.zzmr.spring.controller.UserController;import com.zzmr.spring.dao.UserDao;import com.zzmr.spring.service.UserService;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class IOCByAnnotationTest { @Test public void test () { ApplicationContext ioc = new ClassPathXmlApplicationContext ("spring-ioc-annotation.xml" ); UserController userController = ioc.getBean("userController" ,UserController.class); userController.saveUser(); } }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xmlns:context ="http://www.springframework.org/schema/context" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd" > <context:component-scan base-package ="com.zzmr.spring" > </context:component-scan > <bean id ="userService" class ="com.zzmr.spring.service.impl.UserServiceImpl" > </bean > <bean id ="userDao" class ="com.zzmr.spring.dao.impl.UserDaoImpl" > </bean > </beans >
AOP 场景模拟 需要模拟啊,那就放进来:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 package com.zzmr.spring.proxy;public class CalculatorImpl implements Calculator { @Override public int add (int i, int j) { System.out.println("日志，方法：add 参数：" + i + "," + j); int result = i + j; System.out.println("方法内部：result:" + result); System.out.println("日志，方法：add 结果：" +result); return result; } @Override public int sub (int i, int j) { System.out.println("日志，方法：sub 参数：" + i + "," + j); int result = i - j; System.out.println("方法内部：result:" + result); System.out.println("日志，方法：sub 结果：" +result); return result; } @Override public int mul (int i, int j) { System.out.println("日志，方法：mul 参数：" + i + "," + j); int result = i * j; System.out.println("方法内部：result:" + result); System.out.println("日志，方法：mul 结果：" +result); return result; } @Override public int div (int i, int j) { System.out.println("日志，方法：div 参数：" + i + "," + j); int result = i / j; System.out.println("方法内部：result:" + result); System.out.println("日志，方法：div 结果：" +result); return result; } }
现有代码缺陷
导致程序员在开发核心功能是分散了精力
附加功能分散在各个业务功能方法中,不利于统一维护
解决思路
解决这两个问题,核心就是:解耦,我们需要把附加功能从业务功能代码中抽取出来
困难
解决问题的困难:要抽取的代码在方法内部,靠以前把子类中的重复代码抽取到父类的方式没法解决,所以需要引入新的技术
代理模式 概念: 二十三种设计模式中的一种,属于结构型模式,它的作用就是通过提供一个代理类,让我们在调用目标方法时,不再是直接对目标方法进行调用,而是通过代理类间接调用,让不属于目标方法核心逻辑的代码从目标方法中剥离出来—解耦,调用目标方法时先调用代理对象的方法,减少对目标方法的调用和打扰,同时让附加功能能够集中在一起也有利于统一维护
相关术语
代理 将非核心逻辑剥离出来以后,封装这些非核心逻辑的类,对象,方法
目标 被代理”套用”了非核心逻辑代码的类,对象,方法
静态代理 创建接口：
1 2 3 4 5 6 7 8 9 10 11 package com.zzmr.spring.proxy;public interface Calculator { int add (int i, int j) ; int sub (int i, int j) ; int mul (int i, int j) ; int div (int i, int j) ; }
创建实现类:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 package com.zzmr.spring.proxy;public class CalculatorImpl implements Calculator { @Override public int add (int i, int j) { int result = i + j; System.out.println("方法内部：result:" + result); return result; } @Override public int sub (int i, int j) { int result = i - j; System.out.println("方法内部：result:" + result); return result; } @Override public int mul (int i, int j) { int result = i * j; System.out.println("方法内部：result:" + result); return result; } @Override public int div (int i, int j) { int result = i / j; System.out.println("方法内部：result:" + result); return result; } }
创建静态代理实现类
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 package com.zzmr.spring.proxy;public class CalculatorStaticProxy implements Calculator { private CalculatorImpl target; public CalculatorStaticProxy (CalculatorImpl target) { this .target = target; } @Override public int add (int i, int j) { int result = 0 ; try { System.out.println("日志，方法：add，参数" + i + "," + j); result = target.add(i, j); System.out.println("日志，方法：add，结果" + result); } catch (Exception e) { e.printStackTrace(); } finally { } return result; } @Override public int sub (int i, int j) { System.out.println("日志，方法：sub，参数" + i + "," + j); int result = target.sub(i, j); System.out.println("日志，方法：sub，结果" + result); return result; } @Override public int mul (int i, int j) { System.out.println("日志，方法：mul，参数" + i + "," + j); int result = target.mul(i, j); System.out.println("日志，方法：mul，结果" + result); return result; } @Override public int div (int i, int j) { System.out.println("日志，方法：div，参数" + i + "," + j); int result = target.div(i, j); System.out.println("日志，方法：div，结果" + result); return result; } }
测试:
1 2 3 4 5 6 7 8 9 10 11 package com.zzmr.spring.proxy;import org.junit.Test;public class ProxyTest { @Test public void testProxy () { CalculatorStaticProxy proxy = new CalculatorStaticProxy (new CalculatorImpl ()); proxy.add(1 ,2 ); } }
此时就可以打印出
1 2 3 日志，方法：add，参数1,2 方法内部：result:3 日志，方法：add，结果3
实现类中并没有上下两行代码,但是输出结果却包含了这两行代码,就是通过代理实现的
1 2 静态代理确实实现了解耦,但是由于代码都写死了,完全不具备任何的灵活性,就拿日志功能来说,将来其他地方也需要附加日志,那还得再声明更多个静态代理类,那就产生了大量重复的代码,日志功能还是分散的,没有统一管理 提出进一步的需求,将日志功能集中到一个代理类中,将来有任何日志需求,都通过这一个代理类来实现,这就需要使用动态代理技术了
动态代理 动态生成
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 package com.zzmr.spring.proxy;import java.lang.reflect.InvocationHandler;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.lang.reflect.Proxy;import java.util.Arrays;public class ProxyFactory { private Object target; public ProxyFactory (Object target) { this .target = target; } public Object getProxy () { ClassLoader classLoader = this .getClass().getClassLoader(); Class<?>[] interfaces = target.getClass().getInterfaces(); InvocationHandler h = new InvocationHandler () { @Override public Object invoke (Object proxy, Method method, Object[] args) throws Throwable { Object result = null ; try { System.out.println("日志，方法：" + method.getName() + ", 参数" + Arrays.toString(args)); result = method.invoke(target, args); System.out.println("日志，方法：" + method.getName() + ", 结果" + result); } catch (Exception e) { e.printStackTrace(); System.out.println("日志，方法：" + method.getName() + ", 异常" + e); }finally { System.out.println("日志，方法：" + method.getName() + ", 方法执行完毕" ); } return result; } }; return Proxy.newProxyInstance(classLoader, interfaces, h); } }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 @Test public void testProxy () { ProxyFactory proxyFactory = new ProxyFactory (new CalculatorImpl ()); Calculator proxy = (Calculator) proxyFactory.getProxy(); proxy.add(1 ,2 ); System.out.println("++=====++++====" ); proxy.sub(2 ,1 ); System.out.println("++=====++++====" ); proxy.div(1 ,0 ); }
动态代理以后也不会是自己手写的,学这个是便于理解AOP
AOP概念 AOP(Aspect Oriented Programming 是一种设计思想,是软件设计领域中的面向切面编程,它是面向对象编程的一种补充和完善,它以通过预编译方式和运行期动态代理方式实现在不修改源代码的情况下给程序动态统一添加额外功能的一种技术)
相关术语
横切关注点
通知
前置通知:在被代理的目标方法前 执行
返回通知:在被代理的目标方法成功结束 后执行(寿终正寝)
异常通知:在被代理的目标方法异常结束 后执行(死于非命)
后置通知:在被代理的目标方法最终结束 后执行(盖棺定论)
环绕通知:使用try…catch…finally结构围绕整个 被代理的目标方法,包括上面四种通知对应的所有位置
Spring版本5.3.x以前
Spring版本5.3.x以后
切面
目标
代理
连接点
切入点
作用
简化代码:把方法中固定位置的重复的代码抽取出来,让被抽取的方法更专注于自己的核心功能,提高内聚性
代码增强,把特定的功能封装到切面类中,看哪里有需要,就往上套,被套用了切面逻辑的方法就被切面给增强了
基于注解的AOP
动态代理(InvocationHandler) JDK原生的实现方式,需要被代理的目标类必须实现接口,因为这个技术要求代理对象和目标对象实现同样的接口(兄弟两个拜把子模式)
cglib 通过继承被代理的目标类(认干爹模式)实现代理,所以不需要目标类实现接口
Aspectj 本质上是静态代理,将代理逻辑织入被代理的目标类编译得到的字节码文件,所以最终效果是动态的,weaver就是织入器,Spring只是借用了AspectJ中的注解
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 package com.zzmr.spring.aop.annotation;import org.aspectj.lang.JoinPoint;import org.aspectj.lang.ProceedingJoinPoint;import org.aspectj.lang.Signature;import org.aspectj.lang.annotation.*;import org.springframework.stereotype.Component;import java.util.Arrays;@Component @Aspect public class LoggerAspect { @Pointcut("execution(* com.zzmr.spring.aop.annotation.CalculatorImpl.*(..))") public void pointCut () { } @Before("pointCut()") public void beforeAdviceMethod (JoinPoint joinPoint) { Signature signature = joinPoint.getSignature(); Object[] args = joinPoint.getArgs(); System.out.println("LoggerAspect 方法," + signature.getName() + "参数：" + Arrays.toString(args)); } @After("pointCut()") public void afterAdviceMethod (JoinPoint joinPoint) { Signature signature = joinPoint.getSignature(); System.out.println("LoggerAspect，方法：" + signature.getName() + "执行完毕" ); } @AfterReturning(value = "pointCut()", returning = "result") public void afterReturningAdviceMethod (JoinPoint joinPoint, Object result) { Signature signature = joinPoint.getSignature(); System.out.println("LoggerAspect，方法：" + signature.getName() + ",结果：" + result); } @AfterThrowing(value = "pointCut()", throwing = "ex") public void afterThrowingAdviceMethod (JoinPoint joinPoint, Throwable ex) { Signature signature = joinPoint.getSignature(); System.out.println("LoggerAspect 方法" + signature.getName() + "异常：" + ex); } @Around("pointCut()") public Object aroundAdviceMethod (ProceedingJoinPoint joinPoint) { Object result = null ; try { System.out.println("环绕通知--->前置通知的位置" ); result = joinPoint.proceed(); System.out.println("环绕通知--->返回通知的位置" ); } catch (Throwable e) { e.printStackTrace(); System.out.println("环绕通知--->异常通知的位置" ); }finally { System.out.println("环绕通知--->后置通知的位置" ); } return result; } }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 package com.zzmr.spring.aop.annotation;import org.aspectj.lang.annotation.Aspect;import org.aspectj.lang.annotation.Before;import org.springframework.core.annotation.Order;import org.springframework.stereotype.Component;@Component @Aspect @Order(1) public class ValidateAspect { @Before("com.zzmr.spring.aop.annotation.LoggerAspect.pointCut()") public void beforeMethod () { System.out.println("ValidateAspect-->前置通知" ); } }
声明式事务 Spring框架对JDBC进行封装,使用JdbcTemplate方便实现对数据库操作
使用JdbcTemplate实现增删改查
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 package com.zzmr.spring.test;import org.junit.Test;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.jdbc.core.JdbcTemplate;import org.springframework.test.context.ContextConfiguration;import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;@RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration("classpath:spring-jdbc.xml") public class JdbcTemplateTest { @Autowired private JdbcTemplate jdbcTemplate; @Test public void testInsert () { String sql = "insert into t_user values(null,?,?,?,?,?)" ; jdbcTemplate.update(sql,"root" ,"123" ,23 ,"男" ,"123@con.com" ); } @Test public void testUpdate () { String sql = "update t_user set username = ? where username = ?" ; jdbcTemplate.update(sql,"zzmr1" ,"zzmr" ); } @Test public void testDelete () { String sql = "delete from t_user where username = ?" ; jdbcTemplate.update(sql,"zzmr1" ); } @Test public void testGetUserById () { String sql = "select * from t_user where id = ?" ; User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper <>(User.class),2 ); System.out.println(user); } @Test public void testGetAllUser () { String sql = "select * from t_user" ; List<User> query = jdbcTemplate.query(sql, new BeanPropertyRowMapper <>(User.class)); query.forEach(System.out::println); } @Test public void testGetCount () { String sql = "select count(*) from t_user" ; Integer count = jdbcTemplate.queryForObject(sql, Integer.class); System.out.println(count); } }
编程式的实现方式存在缺陷：
细节没有被屏蔽，具体操作过程中，所有细节都需要程序员自己来完成，比较繁琐
代码复用性不高，如果没有有效抽取出来，每次实现功能都需要自己编写代码，代码就没有得到复用
声明式事务 既然事务控制的代码有规律可循，代码的结构基本是确定的，所以框架就可以将固定模式的代码抽取出来，进行相关的封装
好处1：提高开发效率
好处2：消除了冗余代码
好处3：框架会综合考虑相关领域中在实际开发环境下有可能遇到的各种问题，进行了健壮性，性能等各个方面的优化
编程式：自己写代码实现功能
声明式：通过配置让框架实现功能
基于注解的声明式事务 tx-annotation.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xmlns:context ="http://www.springframework.org/schema/context" xmlns:tx ="http://www.springframework.org/schema/tx" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd" > <context:component-scan base-package ="com.zzmr.spring" > </context:component-scan > <context:property-placeholder location ="classpath:jdbc.properties" /> <bean id ="dataSource" class ="com.alibaba.druid.pool.DruidDataSource" > <property name ="driverClassName" value ="${jdbc.driver}" > </property > <property name ="url" value ="${jdbc.url}" > </property > <property name ="username" value ="${jdbc.username}" > </property > <property name ="password" value ="${jdbc.password}" > </property > </bean > <bean class ="org.springframework.jdbc.core.JdbcTemplate" > <property name ="dataSource" ref ="dataSource" > </property > </bean > <bean id ="transactionManager" class ="org.springframework.jdbc.datasource.DataSourceTransactionManager" > <property name ="dataSource" ref ="dataSource" > </property > </bean > <tx:annotation-driven transaction-manager ="transactionManager" /> </beans >
BookController.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 package com.zzmr.spring.controller;import com.zzmr.spring.service.BookService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;@Controller public class BookController { @Autowired private BookService bookService; public void buyBook (Integer userId,Integer bookId) { bookService.buyBook(userId,bookId); } }
BookService.java
1 2 3 4 5 6 7 8 9 10 package com.zzmr.spring.service;public interface BookService { void buyBook (Integer userId, Integer bookId) ; }
BookServiceImpl.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 package com.zzmr.spring.service.impl;import com.zzmr.spring.dao.BookDao;import com.zzmr.spring.service.BookService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional;import java.util.concurrent.TimeUnit;@Service public class BookServiceImpl implements BookService { @Autowired private BookDao bookDao; @Override @Transactional( //readOnly = true timeout = 3 ) public void buyBook (Integer userId, Integer bookId) { try { TimeUnit.SECONDS.sleep(5 ); }catch (Exception e){ e.printStackTrace(); } Integer price = bookDao.getPriceByBookId(bookId); bookDao.updateStock(bookId); bookDao.updateBalance(userId,price); } }
BookDao.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 package com.zzmr.spring.dao;public interface BookDao { Integer getPriceByBookId (Integer bookId) ; void updateStock (Integer bookId) ; void updateBalance (Integer userId, Integer price) ; }
BookDaoImpl.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 package com.zzmr.spring.dao.impl;import com.zzmr.spring.dao.BookDao;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.jdbc.core.JdbcTemplate;import org.springframework.stereotype.Repository;@Repository public class BookDaoImpl implements BookDao { @Autowired private JdbcTemplate jdbcTemplate; @Override public Integer getPriceByBookId (Integer bookId) { String sql = "select price from t_book where book_id = ?" ; return jdbcTemplate.queryForObject(sql,Integer.class,bookId); } @Override public void updateStock (Integer bookId) { String sql = "update t_book set stock = stock-1 where book_id = ?" ; jdbcTemplate.update(sql,bookId); } @Override public void updateBalance (Integer userId, Integer price) { String sql = "update t_user set balance = balance- ? where user_id = ?" ; jdbcTemplate.update(sql,price,userId); } }
测试类：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 package com.zzmr.spring.test;import com.zzmr.spring.controller.BookController;import org.junit.Test;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.test.context.ContextConfiguration;import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;@RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration("classpath:tx-annotation.xml") public class TxByAnnotationTest { @Autowired private BookController bookController; @Test public void testBuyBook () { bookController.buyBook(1 ,1 ); } }
2022年9月1日 16点42分
SpringMVC MVC是一种软件架构的思想，将软件按照模型、视图、控制器来划分
一类称为实体类Bean：专门存储业务数据的，如Student、User等
一类称为业务处理Bean：指Service或Dao对象，专门用于处理业务逻辑和数据访问
SpringMVC介绍 SpringMVC是Spring的一个后续产品，是Spring的一个子项目首选方案
这玩意封装了servelt，万变不离其中啊
Spring家族原生产品 ，与IOC容器等基础设施无缝对接基于原生的servlet ，通过了功能强大的前端控制器DispatcherServelt，对请求和响应进行统一处理表述层各细分领域需要解决的问题全方位覆盖，提供全面解决方案
代码清新简洁 ，大幅提升开发效率内部组件化程度高，可插拔是组件即插即用 ，想要什么功能配置相应组件即可
性能卓著 ，尤其适合现代大型，超大型互联网项目要求
配置SpringMVC pom.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 <?xml version="1.0" encoding="UTF-8" ?> <project xmlns ="http://maven.apache.org/POM/4.0.0" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" > <modelVersion > 4.0.0</modelVersion > <groupId > com.zzmr</groupId > <artifactId > spring_mvc_helloworld</artifactId > <version > 1.0-SNAPSHOT</version > <packaging > war</packaging > <properties > <maven.compiler.source > 8</maven.compiler.source > <maven.compiler.target > 8</maven.compiler.target > <project.build.sourceEncoding > UTF-8</project.build.sourceEncoding > </properties > <dependencies > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-webmvc</artifactId > <version > 5.3.1</version > </dependency > <dependency > <groupId > ch.qos.logback</groupId > <artifactId > logback-classic</artifactId > <version > 1.2.3</version > </dependency > <dependency > <groupId > javax.servlet</groupId > <artifactId > javax.servlet-api</artifactId > <version > 3.1.0</version > <scope > provided</scope > </dependency > <dependency > <groupId > org.thymeleaf</groupId > <artifactId > thymeleaf-spring5</artifactId > <version > 3.0.12.RELEASE</version > </dependency > </dependencies > </project >
web.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 <?xml version="1.0" encoding="UTF-8" ?> <web-app xmlns ="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version ="4.0" > <servlet > <servlet-name > SpringMVC</servlet-name > <servlet-class > org.springframework.web.servlet.DispatcherServlet</servlet-class > </servlet > <servlet-mapping > <servlet-name > SpringMVC</servlet-name > <url-pattern > /</url-pattern > </servlet-mapping > </web-app >
创建SpringMVC配置文件
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xmlns:context ="http://www.springframework.org/schema/context" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd" > <context:component-scan base-package ="com.zzmr.controller" /> <bean id ="viewResolver" class ="org.thymeleaf.spring5.view.ThymeleafViewResolver" > <property name ="order" value ="1" /> <property name ="characterEncoding" value ="UTF-8" /> <property name ="templateEngine" > <bean class ="org.thymeleaf.spring5.SpringTemplateEngine" > <property name ="templateResolver" > <bean class ="org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver" > <property name ="prefix" value ="/WEB-INF/templates/" /> <property name ="suffix" value =".html" /> <property name ="templateMode" value ="HTML5" /> <property name ="characterEncoding" value ="UTF-8" /> </bean > </property > </bean > </property > </bean > </beans >
配置web.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 <?xml version="1.0" encoding="UTF-8" ?> <web-app xmlns ="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version ="4.0" > <servlet > <servlet-name > SpringMVC</servlet-name > <servlet-class > org.springframework.web.servlet.DispatcherServlet</servlet-class > </servlet > <servlet-mapping > <servlet-name > SpringMVC</servlet-name > <url-pattern > /</url-pattern > </servlet-mapping > </web-app >
编写Controller类
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 package com.zzmr.controller;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;@Controller public class HelloController { @RequestMapping("/") public String portal () { return "index" ; } @RequestMapping("/hello") public String hello () { return "success" ; } }
浏览器发送请求,若请求地址符合前端控制器的url-pattern,该请求就会被前端控制器DispatcherServlet处理,前端控制器就会读取SpringMVC的核心配置文件,通过扫描组件找到控制器,将请求地址和控制器中@RequestMapping注解的value属性值进行匹配,若匹配成功,该注解所标识的控制器方法就是处理请求的方法.处理请求的方法需要返回一个字符串类型的视图名称,该视图名称会被视图解析器解析,加上前缀和后缀组成视图的路径,通过Thymeleaf对视图进行渲染,最终转发到视图所对应页面
@RequsetMapping注解 @RequestMapping注解的作用就是将请求和处理请求的控制器方法关联起来,建立映射关系
@RequestMapping注解的位置及参数
@RequestMapping标识一个类,设置映射请求的请求路径的初始信息
@RequestMapping标识一个方法,设置映射请求路径的具体信息
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 package com.zzmr.controller;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;@Controller public class TestRequestMappingController { @RequestMapping(value = {"/hello", "/abc"}, method = {RequestMethod.POST,RequestMethod.GET}) public String hello () { return "success" ; } }
又出现请求方式了,记住一点就好,POST的情况:表单提交把提交方式改成了POST,或者其他手动更改成了POST,其余均是GET
以下是测试用到的两个页面
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 <!DOCTYPE html > <html lang ="en" xmlns:th ="http://www.thymeleaf.org" > <head > <meta charset ="UTF-8" > <title > 首页</title > </head > <body > <h1 > index.html</h1 > <a th:href ="@{/hello}" href ="" > 测试@RequestMapping注解标识的位置</a > <br > <a th:href ="@{/abc}" > 测试@RequestMapping注解的value属性</a > <br > <form th:action ="@{/hello}" method ="post" > <input type ="submit" value ="测试@RequestMapping注解的method属性" > </form > </body > </html >
1 2 3 4 5 6 7 8 9 10 <!DOCTYPE html > <html lang ="en" xmlns:th ="http://www.thymeleaf.org" > <head > <meta charset ="UTF-8" > <title > 首页</title > </head > <body > <h1 > success.html</h1 > </body > </html >
其他属性用的也不多，就不写了
SpringMVC支持ant风格的路径 1 2 3 4 ? : 表示任意的单个字符 * : 表示任意的0个或多个字符 ** ： 表示任意层数的任意目录 注意 : 在使用 ** 时，只能使用 /**/xxx的方式
1 2 3 4 @RequestMapping("/**/test/ant") public String testAnt () { return "success" ; }
SpringMVC支持路径中的占位符 原始方式：/deleteUser?id=1
所有的代码都在这了
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 package com.zzmr.controller;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;@Controller public class TestRequestMappingController { @RequestMapping( value = {"/hello", "/abc"}, method = {RequestMethod.POST, RequestMethod.GET} ) @GetMapping public String hello () { return "success" ; } @RequestMapping("/**/test/ant") public String testAnt () { return "success" ; } @RequestMapping("/test/rest/{username}/{id}") public String testRest (@PathVariable("id") Integer id, @PathVariable("username") String username) { System.out.println("id:" + id); System.out.println("username:" + username); return "success" ; } }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 <!DOCTYPE html > <html lang ="en" xmlns:th ="http://www.thymeleaf.org" > <head > <meta charset ="UTF-8" > <title > 首页</title > </head > <body > <h1 > index.html</h1 > <a th:href ="@{/hello}" href ="" > 测试@RequestMapping注解标识的位置</a > <br > <a th:href ="@{/abc}" > 测试@RequestMapping注解的value属性</a > <br > <form th:action ="@{/hello}" method ="post" > <input type ="submit" value ="测试@RequestMapping注解的method属性" > </form > <br > <a th:href ="@{/aga/test/ant}" > 测试@RequestMapping注解支持ant风格路径</a > <br > <a th:href ="@{/test/rest//admin/1}" > 测试@RequestMapping注解的value属性中的占位符</a > </body > </html >
SpringMVC获取请求参数 通过ServletAPI获取 1 2 3 4 5 6 7 8 9 10 11 12 13 @RequestMapping("/param/servletAPI") public String getParamByServletAPI (HttpServletRequest request) { String username = request.getParameter("username" ); String password = request.getParameter("password" ); System.out.println("username:" + username + ",password:" + password); return "success" ; }
但是使用原生Servelt是没有必要的,毕竟都学了SpringMVC了,肯定会有更简单的方法来获取参数的.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 package com.zzmr.controller;import com.zzmr.pojo.User;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.CookieValue;import org.springframework.web.bind.annotation.RequestHeader;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;@Controller public class TestParamController { @RequestMapping("/param/servletAPI") public String getParamByServletAPI (HttpServletRequest request) { HttpSession session = request.getSession(); String username = request.getParameter("username" ); String password = request.getParameter("password" ); System.out.println("username:" + username + ",password:" + password); return "success" ; } @RequestMapping("/param") public String getParam ( @RequestParam(value = "userName", required = false, defaultValue = "hello") String username, String password, @RequestHeader(value = "referer") String referer, @CookieValue("JSESSIONID") String jsessionId ) { System.out.println("jsessionId:" +jsessionId); System.out.println("username:" + username + ",password:" + password); System.out.println("referer:" + referer); return "success" ; } @RequestMapping("/param/pojo") public String getParamByPojo (User user) { System.out.println(user); return "success" ; } }
1 2 3 4 5 小插曲 2022年9月4日 21点43分 这几天都在搞博客，使用Hexo框架以及Github pages 搭建的，算是了解了一点东西，但是用处不大吧··· 这个网课还带继续看啊，虽然现在看的不太明白··· 加油就好!
解决获取请求参数的乱码问题 解决获取请求参数的乱码问题，可以使用SpringMVC提供的
在web.xml中配置Spring的编码过滤器
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 <filter > <filter-name > CharacterEncodingFilter</filter-name > <filter-class > org.springframework.web.filter.CharacterEncodingFilter</filter-class > <init-param > <param-name > encoding</param-name > <param-value > UTF-8</param-value > </init-param > <init-param > <param-name > forceEncoding</param-name > <param-value > true</param-value > </init-param > </filter > <filter-mapping > <filter-name > CharacterEncodingFilter</filter-name > <url-pattern > /*</url-pattern > </filter-mapping >
域对象共享数据 使用ServletAPI向request域对象共享数据 这种还用写？就是之前的request.setAttribute(“testScope”,”hello,serveltAPI”);
使用ModelAndView向request域对象共享数据 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 package com.zzmr.controller;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.ui.ModelMap;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.servlet.ModelAndView;import javax.servlet.ServletContext;import javax.servlet.http.HttpSession;import java.util.Map;@Controller public class TestScopeController { @RequestMapping("/test/mav") public ModelAndView testMAC () { ModelAndView mav = new ModelAndView (); mav.addObject("testRequestScope" , "hello,ModelAndView" ); mav.setViewName("success" ); return mav; } @RequestMapping("/test/model") public String testModel (Model model) { System.out.println(model.getClass().getName()); model.addAttribute("testRequestScope" , "hello,Model" ); return "success" ; } @RequestMapping("/test/modelMap") public String testModelMao (ModelMap modelMap) { System.out.println(modelMap.getClass().getName()); modelMap.addAttribute("testRequestScope" , "hello,ModelMap" ); return "success" ; } @RequestMapping("/test/map") public String testMap (Map<String, Object> map) { System.out.println(map.getClass().getName()); map.put("testRequestScope" , "hello,map" ); return "success" ; } @RequestMapping("/test/session") public String testSession (HttpSession session) { session.setAttribute("testSessionScope" , "hello,session" ); return "success" ; } @RequestMapping("/test/application") public String testApplication (HttpSession session) { ServletContext servletContext = session.getServletContext(); servletContext.setAttribute("testApplicationScope" , "hello,application" ); return "success" ; } }
网页文件：
1 2 3 4 5 6 <a th:href ="@{/test/mav}" > 测试通过ModelAndView向请求域共享数据</a > <br > <a th:href ="@{/test/model}" > 测试通过Model向请求域共享数据</a > <br > <a th:href ="@{/test/modelMap}" > 测试通过ModelMap向请求域共享数据</a > <br > <a th:href ="@{/test/map}" > 测试通过Map向请求域共享数据</a > <br > <a th:href ="@{/test/session}" > 测试向会话域共享数据</a > <br > <a th:href ="@{/test/application}" > 测试向应用域共享数据</a > <br >
跳转的网页：
1 2 3 4 <h1 > success.html</h1 > <p th:text ="${testRequestScope}" > </p > <p th:text ="${session.testSessionScope}" > </p > <p th:text ="${application.testApplicationScope}" > </p >
SpringMVC的视图 SpringMVC中的视图是View接口，视图的作用是渲染数据，将模型Model中的数据展示给用户
ThymeleafView 当控制器方法中所设置的视图名称没有任何前缀时，此时的视图名称会被SpringMVC配置文件中所配置的视图解析器解析，视图名称拼接试图前缀和视图
1 2 3 4 @RequestMapping("/test/view/thymeleaf") public String testThymeleafView () { return "success" ; }
配置ThymeleafView视图
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 <bean id ="viewResolver" class ="org.thymeleaf.spring5.view.ThymeleafViewResolver" > <property name ="order" value ="1" /> <property name ="characterEncoding" value ="UTF-8" /> <property name ="templateEngine" > <bean class ="org.thymeleaf.spring5.SpringTemplateEngine" > <property name ="templateResolver" > <bean class ="org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver" > <property name ="prefix" value ="/WEB-INF/templates/" /> <property name ="suffix" value =".html" /> <property name ="templateMode" value ="HTML5" /> <property name ="characterEncoding" value ="UTF-8" /> </bean > </property > </bean > </property > </bean >
重定向视图 1 <a th:href ="@{/test/view/redirect}" > 测试SpringMVC的视图RedirectView</a > <br >
使用 “redirect:***“
1 2 3 4 @RequestMapping("/test/view/redirect") public String testRedDirectView () { return "redirect:/test/model" ; }
一般来说,使用转发视图时,使用Thymeleaf视图,使用重定向时,使用重定向视图,而访问页面失败时,就使用转发,访问成功就适用重定向
视图控制器view-controller 当控制器方法中,仅仅用来实现页面跳转,即只需要设置视图名称时,可以将处理器方法使用view-controller标签进行表示
1 2 3 4 5 6 7 8 <mvc:annotation-driven /> <mvc:view-controller path ="/" view-name ="index" > </mvc:view-controller >
配置好这个,就不用单独写一个类来设置跳转了,但是要注意必须要加上” <mvc:annotation-driven />”标签
RESTful RESTful简介
资源
资源是一种看待服务器的方式，即将服务器看作是由很多离散的资源组成
资源的表述
资源的表述是一段资源在某个特定时刻的状态的描述，可以在客户端-服务器端之间转移(交换)
状态转移
转台转移说的是:在客户端和服务器端之间转移(transfer)代表资源状态的表述,通过转移和操作资源的表述,来间接实现操作资源的目的
RESTful的实现 具体说,就是HTTP协议里面,四个表示操作方式的动词:GET,POST,PUT,DELETE
REST风格提倡URL地址是用统一的风格设计,从前到后各个单词使用斜杠分开,不适用问好键值对方式携带请求参数,而是将要发送给服务器的数据作为URL地址的一部分,以保证整体风格的一致性
代码 GET和POST都跟之前没什么区别
若要发送put和delete请求，需要在web.xml中配置一个过滤器：HiddenHttpMethodFilter
当前请求必须为post
当前请求必须传输请求参数_method _method的值才是最终的请求方式
1 2 3 4 <form th:action ="@{/user}" method ="post" > <input type ="hidden" name ="_method" value ="put" > <input type ="submit" value ="修改用户信息" > </form >
1 2 3 4 5 6 7 8 9 <filter > <filter-name > HiddenHttpMethodFilter</filter-name > <filter-class > org.springframework.web.filter.HiddenHttpMethodFilter</filter-class > </filter > <filter-mapping > <filter-name > HiddenHttpMethodFilter</filter-name > <url-pattern > /*</url-pattern > </filter-mapping >
此时就可以使用了
1 2 3 4 5 @RequestMapping(value = "/user",method = RequestMethod.PUT) public String updateUser () { System.out.println("修改用户信息===> /user---->put" ); return "success" ; }
测试代码:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 <h1 > index.html</h1 > <a th:href ="@{/user}" > 查询所有的用户信息</a > <br > <a th:href ="@{/user/1}" > 查询id为1的用户信息</a > <br > <form th:action ="@{/user}" method ="post" > <input type ="submit" value ="添加用户信息" > </form > <form th:action ="@{/user}" method ="post" > <input type ="hidden" name ="_method" value ="put" > <input type ="submit" value ="修改用户信息" > </form > <form th:action ="@{/user/5}" method ="post" > <input type ="hidden" name ="_method" value ="delete" > <input type ="submit" value ="删除用户信息" > </form >
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 package com.zzmr.controller;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;@Controller public class TestRestController { @RequestMapping(value = "/user", method = RequestMethod.GET) public String getAllUser () { System.out.println("实现查询所有的用户信息===> /user---->get" ); return "success" ; } @RequestMapping(value = "/user/{id}", method = RequestMethod.GET) public String getUserById (@PathVariable("id") Integer id) { System.out.println("根据id查询用户信息===> /user/" + id + "---->get" ); return "success" ; } @RequestMapping(value = "/user", method = RequestMethod.POST) public String insertUser () { System.out.println("添加用户信息===> /user---->post" ); return "success" ; } @RequestMapping(value = "/user", method = RequestMethod.PUT) public String updateUser () { System.out.println("修改用户信息===> /user---->put" ); return "success" ; } @RequestMapping(value = "/user/{id}", method = RequestMethod.DELETE) public String deleteUser (@PathVariable Integer id) { System.out.println("删除用户信息===> /user/" + id + "---->delete" ); return "success" ; } }
派生注解 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 @GetMapping("/user") public String getAllUser () { System.out.println("实现查询所有的用户信息===> /user---->get" ); return "success" ; } @GetMapping("/user/{id}") public String getUserById (@PathVariable("id") Integer id) { System.out.println("根据id查询用户信息===> /user/" + id + "---->get" ); return "success" ; } @PostMapping("/user") public String insertUser () { System.out.println("添加用户信息===> /user---->post" ); return "success" ; } @PutMapping("/user") public String updateUser () { System.out.println("修改用户信息===> /user---->put" ); return "success" ; } @DeleteMapping("/user/{id}") public String deleteUser (@PathVariable Integer id) { System.out.println("删除用户信息===> /user/" + id + "---->delete" ); return "success" ; }
RESTful案例 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 <mvc:default-servlet-handler /> <mvc:annotation-driven /> <mvc:view-controller path ="/" view-name ="index" > </mvc:view-controller >
引入了静态资源,但是之前配置的DispatcherServlet前端控制器无法解析静态资源,所以引入的静态资源就无法使用,可以配置上面的标签,但是还是要开启mvc的注解驱动才能用
任重道远
RESTful增删改查,这个还没用到数据库,只是模拟一下,到后面会整合SSM,到那时再详细的使用
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 package com.zzmr.controller;import com.zzmr.dao.EmployeeDao;import com.zzmr.pojo.Employee;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.stereotype.Repository;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import java.util.Collection;@Controller public class EmployeeController { @Autowired private EmployeeDao employeeDao; @RequestMapping(value = "/employee", method = RequestMethod.GET) public String getAllEmployee (Model model) { Collection<Employee> allEmployee = employeeDao.getAll(); model.addAttribute("allEmployee" , allEmployee); return "employee_list" ; } @RequestMapping(value = "/employee", method = RequestMethod.POST) public String addEmployee (Employee employee) { employeeDao.save(employee); return "redirect:/employee" ; } @RequestMapping(value = "/employee/{id}", method = RequestMethod.GET) public String toupdate (@PathVariable("id") Integer id, Model model) { Employee employee = employeeDao.get(id); model.addAttribute("employee" , employee); return "employee_update" ; } @RequestMapping(value = "/employee", method = RequestMethod.PUT) public String updateEmployee (Employee employee) { employeeDao.save(employee); return "redirect:/employee" ; } @RequestMapping(value = "/employee/{id}", method = RequestMethod.DELETE) public String deleteEmployee (@PathVariable("id") Integer id) { employeeDao.delete(id); return "redirect:/employee" ; } }
这里记住有用的东西
重定向:
1 return "redirect:/employee";
将数据在请求域中共享
在参数中加入Model modelpublic String toupdate(@PathVariable("id") Integer id, Model model)
SpringMVC处理ajax请求 RequestBody获取json格式的请求参数 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 <!DOCTYPE html > <html lang ="en" xmlns:th ="http://www.thymeleaf.org" > <head > <meta charset ="UTF-8" > <title > 首页</title > </head > <body > <div id ="app" > <h1 > index.html</h1 > <input type ="button" value ="测试SpringMVC处理ajax" @click ="testAjax()" > <br > <input type ="button" value ="使用@RequestBody注解处理 Json格式的请求参数" @click ="testRequestBody()" > <br > </div > <script type ="text/javascript" th:src ="@{/js/vue.js}" > </script > <script type ="text/javascript" th:src ="@{/js/axios.min.js}" > </script > <script type ="text/javascript" > var vue = new Vue ({ el : "#app" , methods : { testAjax ( axios.post ( "/SpringMVC/test/ajax?id=1001" , {username : "admin" , password : "123456" } ).then (response => console .log (response.data ); }); }, testRequestBody ( axios.post ( "/SpringMVC/test/RequestBody/json" , {username : "admin" , password : "123456" , age : 23 , gender : "男" } ).then (response => console .log (response.data ); }); } } }); </script > </body > </html >
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 package com.zzmr.controller;import com.zzmr.pojo.User;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestBody;import org.springframework.web.bind.annotation.RequestMapping;import javax.servlet.http.HttpServletResponse;import java.io.IOException;import java.util.Map;import java.util.Objects;@Controller public class TestAjaxController { @RequestMapping("/test/ajax") public void testAjax (Integer id, @RequestBody String requestBody, HttpServletResponse response) throws IOException { System.out.println("id" + id); System.out.println("username" + requestBody); response.getWriter().write("hello,axios" ); } @RequestMapping("/test/RequestBody/json") public void testRequestBody (@RequestBody Map<String, Object> map, HttpServletResponse response) throws IOException { System.out.println(map); response.getWriter().write("hello,RequestBody" ); } public void testRequestBody (@RequestBody User user,HttpServletResponse response) throws IOException { System.out.println(user); response.getWriter().write("hello,RequestBody" ); } }
以后请求方式基本上都是ajax,还有json,所以这是非常重要的,要记好@ResquestBody注解的用法有更简单的方法
ResponseBody响应浏览器的json数据 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 @RequestMapping("/test/ResponseBody") @ResponseBody public String testResponseBody () { return "success" ; } @RequestMapping("/test/ResponseBody/json") @ResponseBody public List<User> testResponseBodyJson () { User user1 = new User (1001 , "admin" , "123456" , 21 , "男" ); User user2 = new User (1001 , "admin" , "123456" , 21 , "男" ); User user3 = new User (1001 , "admin" , "123456" , 21 , "男" ); List<User> lsit = Arrays.asList(user1, user2, user3); return lsit; }
非常方便
1 2 3 4 5 6 7 8 <a th:href ="@{/test/ResponseBody}" > 测试@ResponseBody响应浏览器数据</a > <br > <input type ="button" value ="使用@ResponseBody注解响应Json格式的请求参数" @click ="testResponseBody()" > <br > ========================================= testResponseBody() { axios.post("/SpringMVC/test/ResponseBody/json").then(response => { console.log(response.data); }); }
总之就是请求和响应的方法
@RestController注解 @RestController注解是SpringMVC提供的一个复合注解,标识在控制器的类上,就相当于为类添加了@Controller注解,并且为其中的每个方法添加了@ResponseBody注解
文件上传和下载 ResponseEntity用于控制器方法的返回值类型,该控制器方法的返回值就是响应到浏览器的响应报文
文件上传 这个代码属于是模板代码,以后用到直接拿就行
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 package com.zzmr.controller;import org.springframework.http.HttpHeaders;import org.springframework.http.HttpStatus;import org.springframework.http.ResponseEntity;import org.springframework.stereotype.Controller;import org.springframework.util.MultiValueMap;import org.springframework.web.bind.annotation.RequestMapping;import javax.servlet.ServletContext;import javax.servlet.http.HttpSession;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;@Controller public class FileUpAndDownController { @RequestMapping("/test/down") public ResponseEntity<byte []> testResponseEntity(HttpSession session) throws IOException { ServletContext servletContext = session.getServletContext(); String realPath = servletContext.getRealPath("img" ); realPath = realPath + File.separator + "11.png" ; InputStream is = new FileInputStream (realPath); byte [] bytes = new byte [is.available()]; is.read(bytes); MultiValueMap<String, String> headers = new HttpHeaders (); headers.add("Content-Disposition" , "attachment;filename=11.png" ); HttpStatus statusCode = HttpStatus.OK; ResponseEntity<byte []> responseEntity = new ResponseEntity <>(bytes, headers, statusCode); is.close(); return responseEntity; } }
文件下载 道理还是这个道理,没问题
先是找到路径
上传即可
这是上传的表单
1 2 3 4 <form th:action ="@{/test/up}" method ="post" enctype ="multipart/form-data" > 头像<input type ="file" name ="photo" > <br > <input type ="submit" value ="上传" > </form >
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 @RequestMapping("/test/up") public String testup (MultipartFile photo, HttpSession httpSession) throws IOException { String filename = photo.getOriginalFilename(); ServletContext servletContext = httpSession.getServletContext(); String photoPath = servletContext.getRealPath("photo" ); File file = new File (photoPath); if (!file.exists()) { file.mkdir(); } String fianlPath = photoPath + File.separator + filename; photo.transferTo(new File (fianlPath)); return "success" ; }
但是要进行配置
1 2 3 4 5 6 <dependency > <groupId > commons-fileupload</groupId > <artifactId > commons-fileupload</artifactId > <version > 1.3.1</version > </dependency >
配置spring配置文件
是通过id找到这个解析器的,而且id必须为multipartResolver
1 2 3 4 <!-- 配置文件上传解析器--> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> <!-- <property name="defaultEncoding" value="UTF-8"></property>--> </bean>
文件上传解决重名问题 思路就是先用String的lastindexOf方法把文件的后缀分割出来,然后再获取uuid,拼接到一块就OK了
1 2 3 4 5 String hzNamee = filename.substring(filename.lastIndexOf("." ));String uuid = UUID.randomUUID().toString();filename = uuid + hzNamee;
拦截器 这一块了解一下就OK了
拦截器的配置 SpringMVC中的拦截控制器方法的执行
在SpringMVC配置文件中配置拦截器
1 2 3 <mvc:interceptors > <bean class ="com.zzmr.interceptor.FirstInterceptor" /> </mvc:interceptors >
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 package com.zzmr.interceptor;import org.springframework.web.servlet.HandlerInterceptor;import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class FirstInterceptor implements HandlerInterceptor { @Override public boolean preHandle (HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out.println("FirstInterceptor--->preHandle" ); return true ; } @Override public void postHandle (HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { System.out.println("FirstInterceptor--->postHandle" ); } @Override public void afterCompletion (HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { System.out.println("FirstInterceptor--->afterCompletion" ); } }
preHandle方法的返回值就是是否放行的,true表示放行,false表示拦截
配置方式还有其他:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 <mvc:interceptors > <mvc:interceptor > <mvc:mapping path ="/**" /> <mvc:exclude-mapping path ="/abc" /> <ref bean ="firstInterceptor" /> </mvc:interceptor > </mvc:interceptors >
而上面的mvc:interceptor标签是最精确的
拦截器执行顺序 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 package com.zzmr.interceptor;import org.springframework.stereotype.Component;import org.springframework.web.servlet.HandlerInterceptor;import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;@Component public class FirstInterceptor implements HandlerInterceptor { @Override public boolean preHandle (HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out.println("FirstInterceptor--->preHandle" ); return true ; } @Override public void postHandle (HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { System.out.println("FirstInterceptor--->postHandle" ); } @Override public void afterCompletion (HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { System.out.println("FirstInterceptor--->afterCompletion" ); } }
异常处理 基于配置的异常处理 SpringMVC提供了一个处理控制器方法执行过程中所出现的异常的接口:HandlerExceptionResolver和SimpleMappingExceptionResolver
XML配置方式
控制器方法:
1 2 3 4 5 @RequestMapping("/test/hello") public String testHello () { System.out.println(1 /0 ); return "success" ; }
1 2 3 4 5 6 7 8 9 10 <bean class ="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver" > <property name ="exceptionMappings" > <props > <prop key ="java.lang.ArithmeticException" > error</prop > </props > </property > <property name ="exceptionAttribute" value ="ex" > </property > </bean >
非常简单,说的是配置起来啊
基于注解的配置方式
异常处理组件:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 package com.zzmr.controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.ControllerAdvice;import org.springframework.web.bind.annotation.ExceptionHandler;import org.springframework.web.servlet.ModelAndView;@ControllerAdvice public class ExceptionController { @ExceptionHandler(ArithmeticException.class) public String handleException (Throwable ex, Model model) { model.addAttribute("ex" ,ex); return "error.html" ; } }
注解配置SpringMVC 使用配置类和注解代替web.xml和SpringMVC配置文件的功能初学阶段,只会xml配置就可以了
但是以后用的最多的还是注解吧,大概应该可能是
创建初始化类,代替web.xml 感觉是清晰明了,毕竟是方法里面配置WebConfig就是代替SpringMVC的配置文件的
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 package com.zzmr.config;import org.springframework.web.filter.CharacterEncodingFilter;import org.springframework.web.filter.HiddenHttpMethodFilter;import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;import javax.servlet.Filter;public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer { @Override protected Class<?>[] getRootConfigClasses() { return new Class []{SpringConfig.class}; } @Override protected Class<?>[] getServletConfigClasses() { return new Class []{WebConfig.class}; } @Override protected String[] getServletMappings() { return new String []{"/" }; } @Override protected Filter[] getServletFilters() { CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter (); characterEncodingFilter.setEncoding("UTF-8" ); characterEncodingFilter.setForceEncoding(true ); HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter (); return new Filter []{characterEncodingFilter,hiddenHttpMethodFilter}; } }
过滤器主要是两个
CharacterEncodingFilter
setEncoding(“UTF-8”)
setForceEncoding(true)
HiddenHttpMethodFilter
最后把这两个过滤器return即可
SpringMVC配置文件 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 package com.zzmr.config;import com.zzmr.interceptor.FirstInterceptor;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.ComponentScan;import org.springframework.context.annotation.Configuration;import org.springframework.web.context.ContextLoader;import org.springframework.web.context.WebApplicationContext;import org.springframework.web.multipart.commons.CommonsMultipartResolver;import org.springframework.web.servlet.HandlerExceptionResolver;import org.springframework.web.servlet.ViewResolver;import org.springframework.web.servlet.config.annotation.*;import org.springframework.web.servlet.handler.SimpleMappingExceptionResolver;import org.thymeleaf.spring5.SpringTemplateEngine;import org.thymeleaf.spring5.view.ThymeleafViewResolver;import org.thymeleaf.templatemode.TemplateMode;import org.thymeleaf.templateresolver.ITemplateResolver;import org.thymeleaf.templateresolver.ServletContextTemplateResolver;import java.util.List;import java.util.Properties;@Configuration @ComponentScan("com.zzmr.controller") @EnableWebMvc public class WebConfig implements WebMvcConfigurer { @Override public void configureDefaultServletHandling (DefaultServletHandlerConfigurer configurer) { configurer.enable(); } @Override public void addViewControllers (ViewControllerRegistry registry) { registry.addViewController("/" ).setViewName("index" ); } @Bean public CommonsMultipartResolver multipartResolver () { return new CommonsMultipartResolver (); } @Override public void addInterceptors (InterceptorRegistry registry) { FirstInterceptor firstInterceptor = new FirstInterceptor (); registry.addInterceptor(firstInterceptor).addPathPatterns("/**" ); } @Override public void configureHandlerExceptionResolvers (List<HandlerExceptionResolver> resolvers) { SimpleMappingExceptionResolver exceptionResolver = new SimpleMappingExceptionResolver (); Properties prop = new Properties (); prop.setProperty("java.lang.ArithmeticException" , "error" ); exceptionResolver.setExceptionMappings(prop); exceptionResolver.setExceptionAttribute("ex" ); resolvers.add(exceptionResolver); } @Bean public ITemplateResolver templateResolver () { WebApplicationContext webApplicationContext = ContextLoader.getCurrentWebApplicationContext(); ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver (webApplicationContext.getServletContext()); templateResolver.setPrefix("/WEB-INF/templates/" ); templateResolver.setSuffix(".html" ); templateResolver.setCharacterEncoding("UTF-8" ); templateResolver.setTemplateMode(TemplateMode.HTML); return templateResolver; } @Bean public SpringTemplateEngine templateEngine (ITemplateResolver templateResolver) { SpringTemplateEngine templateEngine = new SpringTemplateEngine (); templateEngine.setTemplateResolver(templateResolver); return templateEngine; } @Bean public ViewResolver viewResolver (SpringTemplateEngine templateEngine) { ThymeleafViewResolver viewResolver = new ThymeleafViewResolver (); viewResolver.setCharacterEncoding("UTF-8" ); viewResolver.setTemplateEngine(templateEngine); return viewResolver; } }
这里面一堆东西
Spring配置文件 这个里面倒是没多少东西
1 2 3 4 5 6 7 8 9 10 11 12 package com.zzmr.config;import org.springframework.context.annotation.Configuration;@Configuration public class SpringConfig {}
拦截器 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 package com.zzmr.interceptor;import org.springframework.web.servlet.HandlerInterceptor;import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class FirstInterceptor implements HandlerInterceptor { @Override public boolean preHandle (HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { return true ; } @Override public void postHandle (HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { HandlerInterceptor.super .postHandle(request, response, handler, modelAndView); } @Override public void afterCompletion (HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { HandlerInterceptor.super .afterCompletion(request, response, handler, ex); } }
SpringMVC执行流程 SpringMVC常用组件
DispathcerServlet: 前端控制器,不需要工程师开发,由框架提供
HandlerMapping: 处理器映射,不需要工程师开发,由框架提供
Handler: 处理器,需要工程师开发
HandlerAdapter: 处理器适配器,不需要工程师开发,由框架提供
ViewResovler: 视图解析器,不需要工程师开发,由框架提供
View: 视图
感觉这些源码好难懂啊
SpringMVC的执行流程
用户向服务器发送请求,请求被SpringMVC前端控制器DispatcherServlet捕获
DispathcerServlet对请求URL进行解析,得到请求资源标识符(URI),判断请求URI对应的映射:
不存在
再判断是否配置了mvc:default-servlet-handler
如果没有配置,则控制台报映射查找不到,客户端展示404错误
如果有配置,则访问目标资源(一般为静态资源,如js,css,html)找不到客户端也会展示404错误
存在则执行下面的流程
根据该URI,调用HanlderMapping获得该Handler配置的所有相关的对象(包括Handler对象以及Handler对象对应的拦截器)最后以HandlerExecutionChain执行链对象的形式返回
DispatcherServlet根据获得的Handler,选择一个合适的HandlerAdapter
如果成功获取HandlerAdapter,此时开始执行拦截器的preHandler()方法[正向]
提取Request中的模型数据,填充Handler入参,开始执行Handler(Controller)方法,处理请求,在填充Handler的入参过程中,根据配置,Spring将帮你做额外的工作:
HttpMessageConveter: 将请求消息(如json.xml等数据)转换成一个对象,将对象转换成指定的响应信息
数据转换:对请求消息进行数据转换,如String转换成Integer,Double等
数据格式化:对请求消息进行数据格式化,如将字符串转化成格式化数字或格式化日期等
数据验证:验证数据的有效性(长度,格式等) 验证结果存储到BindingResult或Error中
Handler执行完成后,向DispatcherServlet返回一个ModelAndView对象
此时将开始执行拦截器的postHandle()方法[逆向]
根据返回的ModelAndView(此时会判断是否存在异常,如果存在异常,则执行HandlerExceptionResovler进行异常处理)选择一个适合的ViewResover进行试图解析,根据Model和View来渲染视图
渲染视图完毕执行拦截器的afterCompletion()方法(逆向)
将渲染结果返回给客户端
SSM整合 ContextLoaderListener Spring提供了监听器COntextLoaderListener,实现ServletContextListener接口,课监听ServletContext的状态,在web服务器的启动,读取Spring的配置文件,创建Spring的IOC容器,web应用中必须在web.xml中配置
配置文件:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 <listener > <listener-class > org.springframework.web.context.ContextLoaderListener</listener-class > </listener > <context-param > <param-name > contextConfigLocation</param-name > <param-value > classpath:spring.xml</param-value > </context-param >
下面测试这个监听器
web.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 <?xml version="1.0" encoding="UTF-8" ?> <web-app xmlns ="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version ="4.0" > <servlet > <servlet-name > SpringMVC</servlet-name > <servlet-class > org.springframework.web.servlet.DispatcherServlet</servlet-class > <init-param > <param-name > contextConfigLocation</param-name > <param-value > classpath:springmvc.xml</param-value > </init-param > <load-on-startup > 1</load-on-startup > </servlet > <servlet-mapping > <servlet-name > SpringMVC</servlet-name > <url-pattern > /</url-pattern > </servlet-mapping > <listener > <listener-class > org.springframework.web.context.ContextLoaderListener</listener-class > </listener > <context-param > <param-name > contextConfigLocation</param-name > <param-value > classpath:spring.xml</param-value > </context-param > </web-app >
springmvc.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xmlns:context ="http://www.springframework.org/schema/context" xmlns:mvc ="http://www.springframework.org/schema/mvc" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd" > <context:component-scan base-package ="com.zzmr.controller" /> <bean id ="viewResolver" class ="org.thymeleaf.spring5.view.ThymeleafViewResolver" > <property name ="order" value ="1" /> <property name ="characterEncoding" value ="UTF-8" /> <property name ="templateEngine" > <bean class ="org.thymeleaf.spring5.SpringTemplateEngine" > <property name ="templateResolver" > <bean class ="org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver" > <property name ="prefix" value ="/WEB-INF/templates/" /> <property name ="suffix" value =".html" /> <property name ="templateMode" value ="HTML5" /> <property name ="characterEncoding" value ="UTF-8" /> </bean > </property > </bean > </property > </bean > <mvc:annotation-driven /> <mvc:view-controller path ="/" view-name ="index" > </mvc:view-controller > </beans >
spring.xml 1 2 3 4 5 6 7 8 9 10 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xmlns:context ="http://www.springframework.org/schema/context" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd" > <context:component-scan base-package ="com.zzmr.service.impl" > </context:component-scan > </beans >
SSM整合准备 pom.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 <?xml version="1.0" encoding="UTF-8" ?> <project xmlns ="http://maven.apache.org/POM/4.0.0" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" > <modelVersion > 4.0.0</modelVersion > <groupId > com.zzmr.ssm</groupId > <artifactId > ssm_last</artifactId > <version > 1.0-SNAPSHOT</version > <packaging > war</packaging > <properties > <spring.version > 5.3.1</spring.version > </properties > <dependencies > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-context</artifactId > <version > ${spring.version}</version > </dependency > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-beans</artifactId > <version > ${spring.version}</version > </dependency > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-web</artifactId > <version > ${spring.version}</version > </dependency > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-webmvc</artifactId > <version > ${spring.version}</version > </dependency > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-jdbc</artifactId > <version > ${spring.version}</version > </dependency > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-aspects</artifactId > <version > ${spring.version}</version > </dependency > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-test</artifactId > <version > ${spring.version}</version > </dependency > <dependency > <groupId > org.mybatis</groupId > <artifactId > mybatis</artifactId > <version > 3.5.7</version > </dependency > <dependency > <groupId > org.mybatis</groupId > <artifactId > mybatis-spring</artifactId > <version > 2.0.6</version > </dependency > <dependency > <groupId > com.alibaba</groupId > <artifactId > druid</artifactId > <version > 1.2.5</version > </dependency > <dependency > <groupId > junit</groupId > <artifactId > junit</artifactId > <version > 4.12</version > <scope > test</scope > </dependency > <dependency > <groupId > mysql</groupId > <artifactId > mysql-connector-java</artifactId > <version > 8.0.16</version > </dependency > <dependency > <groupId > log4j</groupId > <artifactId > log4j</artifactId > <version > 1.2.17</version > </dependency > <dependency > <groupId > com.github.pagehelper</groupId > <artifactId > pagehelper</artifactId > <version > 5.2.0</version > </dependency > <dependency > <groupId > ch.qos.logback</groupId > <artifactId > logback-classic</artifactId > <version > 1.2.3</version > </dependency > <dependency > <groupId > javax.servlet</groupId > <artifactId > javax.servlet-api</artifactId > <version > 3.1.0</version > <scope > provided</scope > </dependency > <dependency > <groupId > com.fasterxml.jackson.core</groupId > <artifactId > jackson-databind</artifactId > <version > 2.12.1</version > </dependency > <dependency > <groupId > commons-fileupload</groupId > <artifactId > commons-fileupload</artifactId > <version > 1.3.1</version > </dependency > <dependency > <groupId > org.thymeleaf</groupId > <artifactId > thymeleaf-spring5</artifactId > <version > 3.0.12.RELEASE</version > </dependency > </dependencies > </project >
web.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 <?xml version="1.0" encoding="UTF-8" ?> <web-app xmlns ="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version ="4.0" > <filter > <filter-name > CharacterEncodingFilter</filter-name > <filter-class > org.springframework.web.filter.CharacterEncodingFilter</filter-class > <init-param > <param-name > encoding</param-name > <param-value > UTF-8</param-value > </init-param > <init-param > <param-name > forceEncoding</param-name > <param-value > true</param-value > </init-param > </filter > <filter-mapping > <filter-name > CharacterEncodingFilter</filter-name > <url-pattern > /*</url-pattern > </filter-mapping > <filter > <filter-name > HiddenHttpMethodFilter</filter-name > <filter-class > org.springframework.web.filter.HiddenHttpMethodFilter</filter-class > </filter > <filter-mapping > <filter-name > HiddenHttpMethodFilter</filter-name > <url-pattern > /*</url-pattern > </filter-mapping > <servlet > <servlet-name > SpringMVC</servlet-name > <servlet-class > org.springframework.web.servlet.DispatcherServlet</servlet-class > <init-param > <param-name > contextConfigLocation</param-name > <param-value > classpath:springmvc.xml</param-value > </init-param > <load-on-startup > 1</load-on-startup > </servlet > <servlet-mapping > <servlet-name > SpringMVC</servlet-name > <url-pattern > /</url-pattern > </servlet-mapping > <listener > <listener-class > org.springframework.web.context.ContextLoaderListener</listener-class > </listener > <context-param > <param-name > contextConfigLocation</param-name > <param-value > classpath:spring.xml</param-value > </context-param > </web-app >
sql 还是用的之前的ssm数据库,应该是之前分页的使用用的
1 2 3 4 5 6 7 8 CREATE TABLE `t_emp` (`emp_id` int (11 ) NOT NULL AUTO_INCREMENT, `emp_name` varchar (20 ) DEFAULT NULL , `age` int (11 ) DEFAULT NULL , `sex` char (1 ) DEFAULT NULL , `email` varchar (50 ) DEFAULT NULL , PRIMARY KEY (`emp_id`)) ENGINE= InnoDB DEFAULT CHARSET= utf8
springmvc.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xmlns:context ="http://www.springframework.org/schema/context" xmlns:mvc ="http://www.springframework.org/schema/mvc" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd" > <context:component-scan base-package ="com.zzmr.ssm_last.controller" /> <bean id ="viewResolver" class ="org.thymeleaf.spring5.view.ThymeleafViewResolver" > <property name ="order" value ="1" /> <property name ="characterEncoding" value ="UTF-8" /> <property name ="templateEngine" > <bean class ="org.thymeleaf.spring5.SpringTemplateEngine" > <property name ="templateResolver" > <bean class ="org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver" > <property name ="prefix" value ="/WEB-INF/templates/" /> <property name ="suffix" value =".html" /> <property name ="templateMode" value ="HTML5" /> <property name ="characterEncoding" value ="UTF-8" /> </bean > </property > </bean > </property > </bean > <mvc:default-servlet-handler /> <mvc:annotation-driven /> <mvc:view-controller path ="/" view-name ="index" > </mvc:view-controller > <bean id ="multipartResolver" class ="org.springframework.web.multipart.commons.CommonsMultipartResolver" /> </beans >
spring.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 <?xml version="1.0" encoding="UTF-8" ?> <beans xmlns ="http://www.springframework.org/schema/beans" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xmlns:context ="http://www.springframework.org/schema/context" xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd" > <context:component-scan base-package ="com.zzmr.ssm_last" > <context:exclude-filter type ="annotation" expression ="org.springframework.stereotype.Controller" /> </context:component-scan > <context:property-placeholder location ="classpath:jdbc.properties" > </context:property-placeholder > <bean id ="dateSource" class ="com.alibaba.druid.pool.DruidDataSource" > <property name ="driverClassName" value ="${jdbc.driver}" > </property > <property name ="url" value ="${jdbc.url}" > </property > <property name ="username" value ="${jdbc.username}" > </property > <property name ="password" value ="${jdbc.password}" > </property > </bean > <bean class ="org.mybatis.spring.SqlSessionFactoryBean" > <property name ="configLocation" value ="classpath:mybatis-config.xml" > </property > <property name ="dataSource" ref ="dateSource" > </property > <property name ="typeAliasesPackage" value ="com.zzmr.ssm_last.pojo" > </property > </bean > <bean class ="org.mybatis.spring.mapper.MapperScannerConfigurer" > <property name ="basePackage" value ="com.zzmr.ssm_last.mapper" > </property > </bean > </beans >
好家伙,这就相当于Spring配置文件把MyBatis配置文件掏空了,MyBatis大部分配置项都可以用Speing中的bean标签代替
MyBatis-config.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd" > <configuration > <settings > <setting name ="mapUnderscoreToCamelCase" value ="true" /> </settings > <plugins > <plugin interceptor ="com.github.pagehelper.PageInterceptor" > </plugin > </plugins > </configuration >
log4j.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE log4j :configuration SYSTEM "log4j.dtd" > <log4j:configuration xmlns:log4j ="http://jakarta.apache.org/log4j/" > <appender name ="STDOUT" class ="org.apache.log4j.ConsoleAppender" > <param name ="Encoding" value ="UTF-8" /> <layout class ="org.apache.log4j.PatternLayout" > <param name ="ConversionPattern" value ="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) \n" /> </layout > </appender > <logger name ="java.sql" > <level value ="debug" /> </logger > <logger name ="org.apache.ibatis" > <level value ="info" /> </logger > <root > <level value ="debug" /> <appender-ref ref ="STDOUT" /> </root > </log4j:configuration >
出现问题 1 2 connection error (DruidDataSource.java:1846) java.sql.SQLException: validateConnection false
这个是Druid数据库连接池和Spring的版本不匹配
1 2 3 4 5 6 <dependency > <groupId > com.alibaba</groupId > <artifactId > druid</artifactId > <version > 1.2.5</version > </dependency >
没有样式
1 <link rel="stylesheet" th :href="@{/static/css/index_work.css}" >
写完了,2022年10月4日 17点54分
学是学完了,但是感觉和没学一样,而且web的东西又忘了的差不多了,离谱
SSM整合-AIO Spring整合MyBatis 就是只能再敲一遍然后熟悉一下步骤了至于你要是问我pom.xml是哪里来的,这个是maven工程自带的配置文件,专门用于导入jar包的,一个文件管理该工程的所有jar包,不用手动导入了,啊,你不知道maven怎么用?请移步:Maven使用指南
pom.xml 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 <?xml version="1.0" encoding="UTF-8" ?> <project xmlns ="http://maven.apache.org/POM/4.0.0" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" > <modelVersion > 4.0.0</modelVersion > <groupId > com.zzmr.ssm_aio</groupId > <artifactId > ssm_aio</artifactId > <version > 1.0-SNAPSHOT</version > <packaging > war</packaging > <properties > <maven.compiler.source > 8</maven.compiler.source > <maven.compiler.target > 8</maven.compiler.target > <project.build.sourceEncoding > UTF-8</project.build.sourceEncoding > <spring.version > 5.3.1</spring.version > </properties > <dependencies > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-webmvc</artifactId > <version > ${spring.version}</version > </dependency > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-orm</artifactId > <version > ${spring.version}</version > </dependency > <dependency > <groupId > ch.qos.logback</groupId > <artifactId > logback-classic</artifactId > <version > 1.2.3</version > </dependency > <dependency > <groupId > javax.servlet</groupId > <artifactId > javax.servlet-api</artifactId > <version > 3.1.0</version > <scope > provided</scope > </dependency > <dependency > <groupId > org.thymeleaf</groupId > <artifactId > thymeleaf-spring5</artifactId > <version > 3.0.12.RELEASE</version > </dependency > <dependency > <groupId > org.mybatis</groupId > <artifactId > mybatis-spring</artifactId > <version > 2.0.6</version > </dependency > <dependency > <groupId > org.mybatis</groupId > <artifactId > mybatis</artifactId > <version > 3.5.7</version > </dependency > <dependency > <groupId > mysql</groupId > <artifactId > mysql-connector-java</artifactId > <version > 5.1.3</version > </dependency > <dependency > <groupId > com.alibaba</groupId > <artifactId > druid</artifactId > <version > 1.0.31</version > </dependency > <dependency > <groupId > org.springframework</groupId > <artifactId > spring-test</artifactId > <version > ${spring.version}</version > </dependency > <dependency > <groupId > junit</groupId > <artifactId > junit</artifactId > <version > 4.12</version > <scope > test</scope > </dependency > <dependency > <groupId > org.projectlombok</groupId > <artifactId > lombok</artifactId > <version > 1.18.12</version > <scope > provided</scope > </dependency > </dependencies > </project >
配置数据源 就是配置连接数据库的4个重要参数
user
password
url
driverurl里面的ssm就是数据库名称
1 jdbc.driver =com.mysql.cj.jdbc.Driver
1 2 3 4 jdbc.user =root jdbc.password =010203 jdbc.url =jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC jdbc.driver =com.mysql.jdbc.Driver
log4j日志 这个是直接拷贝过来的,应该没什么区别,之前用的时候也是直接拷的
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE log4j :configuration SYSTEM "log4j.dtd" > <log4j:configuration xmlns:log4j ="http://jakarta.apache.org/log4j/" > <appender name ="STDOUT" class ="org.apache.log4j.ConsoleAppender" > <param name ="Encoding" value ="UTF-8" /> <layout class ="org.apache.log4j.PatternLayout" > <param name ="ConversionPattern" value ="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) \n" /> </layout > </appender > <logger name ="java.sql" > <level value ="debug" /> </logger > <logger name ="org.apache.ibatis" > <level value ="info" /> </logger > <root > <level value ="debug" /> <appender-ref ref ="STDOUT" /> </root > </log4j:configuration >
创建Spring配置文件
先在spring的配置文件中加上这两个
1 2 3 4 5 6 7 8 9 10 <context:property-placeholder location ="classpath:jdbc.properties" /> <bean id ="druidDataSource" class ="com.alibaba.druid.pool.DruidDataSource" > <property name ="username" value ="${jdbc.user}" /> <property name ="password" value ="${jdbc.password}" /> <property name ="driverClassName" value ="${jdbc.driver}" /> <property name ="url" value ="${jdbc.url}" /> </bean >
写来写去,连测试都过不了,那还写个锤子
结语 相当于重新开始了,不要什么速度,这个学期能把SSM学完,学透彻,就OK,寒假做项目,只能这么搞了,你看你,都这个时候了,虽然看完了东西,但是却是一点都不会做项目,完全没有思路,前端的东西也不会写….害,做项目之前可能还要重学JS和VUE,这两个一学应该就问题不大了,嗯加油-2022年10月8日 14点16分
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