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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