Mybatis学习（7）spring和mybatis整合

整合思路：

需要spring通过单例方式管理SqlSessionFactory。

spring和mybatis整合生成代理对象，使用SqlSessionFactory创建SqlSession。（spring和mybatis整合自动完成）

持久层的mapper都需要由spring进行管理。

1）加入jar包：

mybatis3.2.7的jar包；spring3.2.0的jar包；

mybatis和spring的整合包：mybatis-spring-1.2.2.jar

2）applicationContext.xml配置文件：

3）其他db.properties;log4j.properties和之前的一样；

一、使用原始dao接口开发（和spring整合后）：

工程结构：

 User.xml:

<!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.ssm.po.User">
        SELECT * FROM USER WHERE id=#{value}
    </select>
</mapper>

SqlMapConfig.xml配置（加入User.xml的映射）：

<?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>
    <typeAliases>
        <package name="com.ssm.po"/>
    </typeAliases>
    
    <!-- 加载 映射文件 -->
    <mappers>
        <mapper resource="sqlMap/User.xml"/>
    </mappers>
</configuration>

UserDao接口：

package com.ssm.dao;

import com.ssm.po.User;

public interface UserDao {
    //根据id查询用户信息
    public User findUserById(int id) throws Exception;
}

UserDaoImpl实现类（继承SqlSessionDaoSupport）：

dao接口实现类需要注入SqlSessoinFactory，通过spring进行注入。

package com.ssm.dao;

import org.apache.ibatis.session.SqlSession;
import org.mybatis.spring.support.SqlSessionDaoSupport;
import com.ssm.po.User;

public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao {

    @Override
    public User findUserById(int id) throws Exception {
        //继承SqlSessionDaoSupport，通过this.getSqlSession()得到sqlSessoin
        SqlSession sqlSession = this.getSqlSession();
        User user = sqlSession.selectOne("test.findUserById", id);
        return user;
    }
}

applicationContext.xml配置：

配置sqlSessionFactory、数据源、等、声明式配置UserDao的bean：

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd 
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd 
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.2.xsd 
        http://www.springframework.org/schema/aop 
        http://www.springframework.org/schema/aop/spring-aop-3.2.xsd 
        http://www.springframework.org/schema/tx 
        http://www.springframework.org/schema/tx/spring-tx-3.2.xsd ">
        
    <!-- 加载配置文件 -->
    <context:property-placeholder location="classpath:db.properties" />        
    
    <!-- 数据源，使用dbcp -->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driver}" />
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
        <property name="maxActive" value="10" />
        <property name="maxIdle" value="5" />
    </bean>
    
    <!-- sqlSessionFactory -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 加载mybatis的配置文件 -->
        <property name="configLocation" value="mybatis/SqlMapConfig.xml"></property>
        <!-- 数据源 -->
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    
    <!-- 原始dao接口 -->
    <bean id="userDao" class="com.ssm.dao.UserDaoImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
    </bean>
</beans>

测试程序：

package com.ssm.dao;

import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.ssm.po.User;

public class UserDaoImplTest {
    private ApplicationContext applicationContext;
    
    //在setUp这个方法得到spring容器
    @Before
    public void setUp() throws Exception {
        applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
    }

    @Test
    public void testFindUserById() throws Exception {
        UserDao userDao = (UserDao) applicationContext.getBean("userDao");
        User user = userDao.findUserById(1);
        System.out.println(user);
    }
}

二、使用mapper接口代理的方式开发：

 UserMapper.xml:

<?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.ssm.mapper.UserMapper">
    <select id="findUserById" parameterType="int" resultType="user">
        SELECT * FROM USER WHERE id=#{value}
    </select>
</mapper>

UserMapper接口：和UserMapper.xml位于同目录下

package com.ssm.mapper;

import com.ssm.po.User;

public interface UserMapper {
    //根据id查询用户信息
    public User findUserById(int id) throws Exception;
}

在SqlMapConfig.xml中加载UserMapper.xml映射文件：

<?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>
    <typeAliases>
        <package name="com.ssm.po"/>
    </typeAliases>
    
    <!-- 加载 映射文件 -->
    <mappers>
        <package name="com.ssm.mapper"/>
    </mappers>
</configuration>

在applicationContext.xml中通过MapperFactoryBean创建代理对象：

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd 
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd 
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.2.xsd 
        http://www.springframework.org/schema/aop 
        http://www.springframework.org/schema/aop/spring-aop-3.2.xsd 
        http://www.springframework.org/schema/tx 
        http://www.springframework.org/schema/tx/spring-tx-3.2.xsd ">
        
    <!-- 加载配置文件 -->
    <context:property-placeholder location="classpath:db.properties" />        
    
    <!-- 数据源，使用dbcp -->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driver}" />
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
        <property name="maxActive" value="10" />
        <property name="maxIdle" value="5" />
    </bean>
    
    <!-- sqlSessionFactory -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 加载mybatis的配置文件 -->
        <property name="configLocation" value="mybatis/SqlMapConfig.xml"></property>
        <!-- 数据源 -->
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    
    <!-- mapper配置 MapperFactoryBean：根据mapper接口生成代理对象-->
    <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <!-- mapperInterface指定mapper接口 -->
        <property name="mapperInterface" value="com.ssm.mapper.UserMapper"/>
        <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
    </bean>
    
</beans>

测试代码：

package com.ssm.mapper;

import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.ssm.po.User;

public class UserMapperTest {
    private ApplicationContext applicationContext;
    
    @Before
    public void setUp() throws Exception {
        applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
    }

    @Test
    public void testFindUserById() throws Exception {
        UserMapper userMapper = (UserMapper) applicationContext.getBean("userMapper");
        User user = userMapper.findUserById(1);
        System.out.println(user);
    }

}

针对上面的applicationContext.xml中通过MapperFactoryBean创建代理对象，需要针对每个mapper进行配置，比较麻烦，

优化：通过MapperScannerConfigurer进行Mapper扫描：

于是applicationContext.xml配置修改为：

<!-- mapper批量扫描，从mapper包中扫描出mapper接口，自动创建代理对象并且在spring容器中注册 
    遵循规范：将mapper.java和mapper.xml映射文件名称保持一致，且在一个目录 中
    自动扫描出来的mapper的bean的id为mapper类名（首字母小写）
    -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 指定扫描的包名 如果扫描多个包，每个包中间使用半角逗号分隔-->
        <property name="basePackage" value="com.ssm.mapper"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>

 而且和spring整合后，使用mapper扫描器，SqlMapConfig.xm这里不需要配置了

<!-- <package name="com.ssm.mapper"/> -->

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