mybatis(12) 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。

整合环境

jar包：

mybatis3.2.7的jar包、spring3.2.0的jar包、commons-dbcp-1.2.2.jar、commons-pool-1.3.jar

mybatis和spring的整合包：早期ibatis和spring整合是由spring官方提供，mybatis和spring整合由mybatis提供。

sqlSessionFactory

在applicationContext.xml配置sqlSessionFactory和数据源,sqlSessionFactory在mybatis和spring的整合包下。

<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>

<!-- sqlSessinFactory -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 加载mybatis的配置文件 -->
<property name="configLocation" value="mybatis/SqlMapConfig.xml" />
<!-- 数据源 -->
<property name="dataSource" ref="dataSource" />
</bean>
</beans>

原始dao开发（和spring整合后）

User.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="test">
<select id="findUserById" parameterType="int" resultType="com.xdy.ssm.po.User">
select * from user where id=#{value}
</select>
</mapper>

在SqlMapconfig.xml中加载User.xml

<?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>
<!-- 别名定义 -->
<typeAliases>
<package name="com.xdy.ssm.po"/>
</typeAliases>

<mappers>
<mapper resource="sqlmap/User.xml"/>
<!-- 批量加载mapper
指定mapper接口的包名，mybatis自动扫描包下边所有mapper接口进行加载
遵循一些规范：需要将mapper接口类名和mapper.xml映射文件名称保持一致，且在一个目录 中
上边规范的前提是：使用的是mapper代理方法

和spring整合后，使用mapper扫描器，这里不需要配置了
-->
<!-- <package name="com.xdy.ssm.mapper"/> -->
</mappers>
</configuration>

 dao(实现类继承SqlSessionDaoSupport)

package com.xdy.ssm.dao;

import com.xdy.ssm.po.User;

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

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

这里spring声明配置方式，配置dao的bean：

让UserDaoImpl实现类继承SqlSessionDaoSupport

package com.xdy.ssm.dao;

import org.apache.ibatis.session.SqlSession;
import org.mybatis.spring.support.SqlSessionDaoSupport;

import com.xdy.ssm.po.User;

public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao {

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

}

配置dao

<!-- 原始dao接口 -->
<bean id="userDao" class="com.xdy.ssm.dao.UserDaoImpl">
<property name="sqlSessionFactory" ref="sqlSessionFactory"/>
</bean><
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/pre>
测试程序

package com.xdy.ssm.dao;

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

import com.xdy.ssm.po.User;

public class UserDaoImplTest {
private ApplicationContext applicationContext;

@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);
}
}

mapper代理开发

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

mapper.java

package com.xdy.ssm.mapper;

import com.xdy.ssm.po.User;

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

通过MapperFactoryBean创建代理对象

<!-- mapper配置  MapperFactoryBean：根据mapper接口生成代理对象-->
<bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
<property name="mapperInterface" value="com.xdy.ssm.mapper.UserMapper"/>
<property name="sqlSessionFactory" ref="sqlSessionFactory"/>
</bean>

此方法问题：需要针对每个mapper进行配置，麻烦。

通过MapperScannerConfigurer进行mapper扫描

<!-- 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.xdy.ssm.mapper"/>
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
</bean>

测试代码

package com.xdy.ssm.mapper;

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

import com.xdy.ssm.po.User;

public class UserMapperTest {
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 {
UserMapper userMapper = (UserMapper) applicationContext.getBean("userMapper");
User user = userMapper.findUserById(1);
System.out.println(user);
}
}