spring和mybatis的整合（包含原始dao的整合方式和mapper代理整合方式）

Posted 2020-06-14

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一.原始dao的开发的整合方式

1.引入jar包

spring的jar包

mybatis的jar包

由mybatis提供的mybatis和spring的整合jar包（mybatis-spring-xxx.jar）

mysql的驱动jar包(mysql-connector-java-5.1.22-bin.jar)

c3p0数据源的jar（c3p0-0.9.5.1.jar）

2.引入配置文件和dao的实现代码

结构如下：

技术分享

UserDao接口的代码

package com.si.demo.dao;
import com.si.demo.entity.User;
public interface UserDao {

    public User findUserById(Integer id);
    
}

UserDaoImpl实现类的代码

package com.si.demo.dao;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import com.si.demo.entity.User;

public class UserDaoImpl implements UserDao {
    
    private SqlSessionFactory sqlSessionFactory;
    

    public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
        this.sqlSessionFactory = sqlSessionFactory;
    }

    @Override
    public User findUserById(Integer id) {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        User user = sqlSession.selectOne("test.findUserById", id);
        return user;
    }
}

mybatis-config.xml中的配置

<?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>
    
    <mappers>
        <mapper resource="user.xml"/>  
    </mappers>
</configuration>

spring-mybatis.xml中的配置

<?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:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="
    http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
    http://www.springframework.org/schema/tx 
    http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
    http://www.springframework.org/schema/aop 
    http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    
    <!-- ========================================配置数据源========================================= -->
    <bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql:///mybatis2" />
        <property name="user" value="root" />
        <property name="password" value="123456" />
    </bean>
    
    <!-- ========================================分隔线========================================= -->
    
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"></property>
        <property name="configLocation" value="classpath:mybatis-config.xml"></property>
    </bean>
    
    <bean id="userDao" class="com.si.demo.dao.UserDaoImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
    </bean>
  
</beans>

user.xml的配置

<?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="test">
    
    <select id="findUserById" parameterType="int" resultType="com.si.demo.entity.User">
     select * from t_user where id = #{id}
    </select>
</mapper>

3.Junit测试

 @Test
    public void findUserByIdTest(){
        ApplicationContext ctx = new ClassPathXmlApplicationContext("spring-mybatis.xml");
        UserDao userDao = (UserDao) ctx.getBean("userDao");
        User user = userDao.findUserById(1);
        System.out.println(user);
    }

二.Mapper代码开发的整合方式

1.引入jar包

spring的jar包

mybatis的jar包

由mybatis提供的mybatis和spring的整合jar包（mybatis-spring-xxx.jar）

mysql的驱动jar包(mysql-connector-java-5.1.22-bin.jar)

c3p0数据源的jar（c3p0-0.9.5.1.jar）

※和上面的方式jar一样

2.引入配置文件和dao的实现代码

结构如下:

技术分享

UserMapper接口的代码

package com.si.demo.mapper;

import com.si.demo.entity.User;

public interface UserMapper {
   
    public User findUserById(Integer id);
    
}

UserMapper.xml配置

<?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.si.demo.mapper.UserMapper">
    <!-- mapper代理开发方式，namespace的值必须是对应接口的全类名 -->
    <select id="findUserById" parameterType="int" resultType="com.si.demo.entity.User">
     select * from t_user where id = #{id}
    </select>
</mapper>

spring-mybatis.xml配置

<?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:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="
    http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
    http://www.springframework.org/schema/tx 
    http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
    http://www.springframework.org/schema/aop 
    http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    
    <!-- ========================================配置数据源========================================= -->
    <bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql:///mybatis2" />
        <property name="user" value="root" />
        <property name="password" value="123456" />
    </bean>
    
    <!-- ========================================分隔线========================================= -->
    
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"></property>
        <property name="configLocation" value="classpath:mybatis-config.xml"></property>
    </bean>
    
    <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="mapperInterface" value="com.si.demo.mapper.UserMapper"></property>
        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
    </bean>
</beans>

mybatis-config.xml

注意：当UserMapper.xml和对应的UserMapper接口在同一个目录下面的时候，此时这个配置文件可以省略

如果不在同一目录，这里需要在mapper里面配上其目录

<?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>
    
    <mappers>
        <mapper resource="UserMapper.xml的目录"/>
        
    </mappers>
</configuration>

3.Junit测试

@Test
    public void findUserByIdTest2(){
        ApplicationContext ctx = new ClassPathXmlApplicationContext("spring-mybatis.xml");
        UserMapper userDao = (UserMapper) ctx.getBean("userMapper");
        User user = userDao.findUserById(1);
        System.out.println(user);
    }

注意：上面的mapper代理开发的整合方式，存在一些问题

实际的开发过程中，不可能只有一个userMapper，可能还有orderMapper,等等，不可能将所有的xxMapper都配置一遍，那样也太麻烦了，

mybatis的整合包给我们提供了一个扫描类MapperScannerConfigurer，用它就可以了

值需要在上面的spring-mybatis.xml中做一丢丢改变就可以了，如下

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.si.demo.mapper"></property>
        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
    </bean>
    <!-- 将下面的mapper的配置，改成上面的扫描方式，通过来扫描mapper接口所在的报包名，当有多个包的时候，用半角逗号分隔即可
     然后再次强调下，这种方式的配置，UserMapper.xml必须和对应的接口放在同一个目录下面
    -->
    <!--
    <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="mapperInterface" value="com.si.demo.mapper.UserMapper"></property>
        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
    </bean>
    -->

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