怎样通过Spring整合Mybatis来实现业务

目录

1.导入依赖

    <dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>3.8.1</version><scope>test</scope></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.33</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.13</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>6.0.13</version></dependency><!--用Spring操作数据库，还需要一个spring-jdbc--><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>6.0.13</version></dependency><!--AOP织入--><dependency><groupId>org.aspectj</groupId><artifactId>aspectjweaver</artifactId><version>1.9.9.1</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>3.0.2</version></dependency></dependencies>

2. spring配置文件

spring整合mybatis之后，就不再需要mybatis的配置文件

<?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/beanshttps://www.springframework.org/schema/beans/spring-beans.xsd"><!--Spring整合Mybatis，省略了Mybatis的核心配置文件，转而在Spring的配置文件中配置Mybatis--><!--datasource--><bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"><property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/user?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/><property name="username" value="root"/><property name="password" value="123456"/></bean><!--sqlSessionFactory--><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="dataSource" /><property name="configLocation" value="classpath:mybatis-config.xml"/><property name="mapperLocations" value="classpath:com/sun/mapper/*.xml"/></bean><!--SqlSessionTemplate:就是我们使用的sqlSession,这个是spring提供的--><bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate"><!--我们只能使用构造器注入，因为没有set方法--><constructor-arg name="sqlSessionFactory" ref="sqlSessionFactory"/></bean>

 上面的配置文件是固定的，配置文件需要三个bean

• dataSource                                     用来连接数据库
• sqlSessionFactory                        用来创建sqlSession
• sqlSession                                      用来创建sqlSession的bean

 3.编写实体类(原mybatis的步骤)

public class User {private int id;private String name;private int age;}

4.编写接口(原mybatis的步骤)

public interface UserMapper {public List<User> selectUser();}

5.编写xml映射文件(原mybatis的步骤)

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.sun.mapper.UserMapper"><select id="selectUser" resultType="user">select * from user.tb_user</select>
</mapper>

6.编写接口实例

public class UserMapperImpl implements UserMapper{//之前使用Mybatis时候，我们用的是sqlSession，现在用Spring整合Mybatis，我们使用Spring提供的SqlSessionTemplate(相当于sqlSession)private SqlSessionTemplate sqlSessionTemplate;public void setSqlSessionTemplate(SqlSessionTemplate sqlSessionTemplate) {this.sqlSessionTemplate = sqlSessionTemplate;}@Overridepublic List<User> selectUser() {UserMapper mapper = sqlSessionTemplate.getMapper(UserMapper.class);return mapper.selectUser();}
}

 

7.将实例注册到spring中

<bean id="UserMapperImpl" class="com.sun.mapper.UserMapperImpl"><property name="sqlSessionTemplate" ref="sqlSession"/></bean>

8.测试

直接获取实例的bean即可

public class MyTest {@Testpublic void selectTest(){ApplicationContext context = new ClassPathXmlApplicationContext("spring-mybatis.xml");UserMapper userMapperImpl = (UserMapper) context.getBean("UserMapperImpl");List<User> users = userMapperImpl.selectUser();for (User user : users) {System.out.println(user);}}
}

总的来说，使用Spring整合Mybatis，思想还是不变，只不过形式是采用了Spring的ioc容器

9.第二种方式

• Spring提供了一个SqlSessionDaoSupport类，可以通过getSqlSession方法直接获取SqlSession，原本我们是通过SqlSessionTemplate作为中间人，现在通过这个方法我们不再需要SqlSessionTemplate

public class UserMapperImpl2 extends SqlSessionDaoSupport implements UserMapper{//这个类继承了SqlSessionDaoSupport，可以直接get一个SqlSession@Overridepublic List<User> selectUser() {SqlSession sqlSession = getSqlSession();UserMapper mapper = sqlSession.getMapper(UserMapper.class);return mapper.selectUser();}
}

 将这个类放到Spring中：

  <bean id="UserMapperImpl2" class="com.sun.mapper.UserMapperImpl2"><property name="sqlSessionFactory" ref="sqlSessionFactory"/></bean>

测试： 

   @Testpublic void selectTest2(){ApplicationContext context = new ClassPathXmlApplicationContext("spring-mybatis.xml");UserMapper userMapperImpl2 = (UserMapper) context.getBean("UserMapperImpl2");List<User> users = userMapperImpl2.selectUser();for (User user : users) {System.out.println(user);}}