spring和mybatis整合

整合思路

需要spring通过单利方式管理sqlSessionFactory
spring和mybatis整合生成代理对象，使用sqlSessionFactory创建sqlsession（自动完成）
持久层mapper需要有spring进行管理

创建新工程

jar包：
mybatis3.2.7
spring3.2.0
mybatis-spring-1.2.2（mybatis和spring的整合包）

工程结构

2016-11-26_133516.png

Spring配置文件：
在classpath下创建applicationContext.xml，定义数据库链接池、SqlSessionFactory
applicationContext.xml

<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 
        maxIdle，最大空闲数，数据库连接的最大空闲时间。超过空闲时间，数据库连
        接将被标记为不可用，然后被释放。设为0表示无限制。
        MaxActive，连接池的最大数据库连接数。设为0表示无限制。
        maxWait ，最大建立连接等待时间。如果超过此时间将接到异常。设为-1表示
        无限制
    -->
    <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 
        在mybatis和spring的整合包中
    -->
    <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>
    
    <!-- 原始dao开发方法 -->
    <bean id="userDao" class="cn.ztc.ssm.dao.UserDaoImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
    </bean>
        
        
        
</beans>```

Mybatis配置文件
在classpath下创建mybatis/SqlMapConfig.xml
SqlMapConfig.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>
<settings>

<setting name="lazyLoadingEnabled" value="true"/>

<setting name="aggressiveLazyLoading" value="false"/>

<setting name="cacheEnabled" value="true"/>
</settings>

<typeAliases>

    <!-- 批量别名的定义（常用）
        name:指定包名，Mybatis会自动扫描包中的po类。自动定义别名，别名就是类名，首字母大写小写都可
     -->
    <package name="cn.ztc.ssm.po"/>
</typeAliases>

<!-- 加载映射文件 -->
<mappers>
    <mapper resource="sqlmap/User.xml"/>
    
    <!-- 批量加载 
        name:mapper接口的包名
    -->
    <package name="cn.ztc.ssm.mapper"/>
    
    
</mappers>

</configuration>

原始的Dao开发

Dao接口实现类继承SqlSessionDaoSupport
使用此种方法即原始dao开发方法，需要编写dao接口，dao接口实现类、映射文件
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="cn.ztc.ssm.po.User">
select * from user where id = #{id}
</select>

</mapper>

UserDao.java

package cn.ztc.ssm.dao;

import cn.ztc.ssm.po.*;

public interface UserDao {

//根据id查用户信息
public User findUserById(int id) throws Exception;

}

UserDaoImpl.java

package cn.ztc.ssm.dao;

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

import cn.ztc.ssm.po.*;

public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao{

@Override
public User findUserById(int id) throws Exception {
    //继承了SqlSessionDaoSupport，通过getSqlSession();方法得到sqlSession
    SqlSession sqlSession = this.getSqlSession();
    User user = sqlSession.selectOne("test.findUserById", id);
    //方法结束，自动关闭sqlSession
    //sqlSession.close();
    return user;
}

}

测试类

package cn.ztc.ssm.dao;

import static org.junit.Assert.*;

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

import cn.ztc.ssm.po.User;

public class UserDaoImplTest {

private ApplicationContext applicationContext;

//在setUp方法中得到spring的容器
@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);
}

}

mapper代理开发

UserMapper.java

package cn.ztc.ssm.mapper;

import java.util.List;

import cn.ztc.ssm.po.User;
import cn.ztc.ssm.po.UserCustom;
import cn.ztc.ssm.po.UserQueryVo;

public interface UserMapper {

//根据id查用户信息
public User findUserById(int id) throws Exception;

}

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="cn.ztc.ssm.mapper.UserMapper">

<select id="findUserById" parameterType="int" resultType="cn.ztc.ssm.po.User">
    select * from user where id = #{id}
</select>

</mapper>

applicationContext.xml添加

<bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">

<property name="mapperInterface" value="cn.ztc.ssm.mapper.UserMapper"></property>
<property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
</bean>```
测试类

package cn.ztc.ssm.mapper;

import static org.junit.Assert.*;

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

import cn.ztc.ssm.po.User;

public class UserMapperTest {

private ApplicationContext applicationContext;
    
    //在setUp方法中得到spring的容器
    @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);
    }

}

此方法问题：要针对每个mapper配置
解决方法：applicationContext.xml中添加

<!-- mapper批量扫描，从mapper包中扫描出mapper接口，自动创建代理对象并在spring容器中注册
        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">
        <!-- 指定扫描包名
            如果扫描多个包，每个包中间使用半角逗号分隔
            可删除sqlmapconfig.xml文件中的批量扫描配置
         -->
        
        <property name="basePackage" value="cn.ztc.ssm.mapper"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>
        ```