【MyBatis框架】mybatis和spring整合

spring和mybatis整合

1.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。

2.整合环境

创建一个新的java工程（接近实际开发的工程结构）

jar包：

mybatis3.2.7的jar包

spring3.2.0的jar包

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。jar包名mybatis-spring-1.2.2.jar

下面加入MyBatis与Spring整合的全部jar包

如图



工程结构：

如图



3.sqlSessionFactory

在applicationContext.xml配置sqlSessionFactory和数据源

sqlSessionFactory在mybatis和spring的整合包下。

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<?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: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>

4.原始dao开发（和spring整合后）

4.1User.xml

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<?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">

<!-- namespace命名空间，作用就是对sql进行分类化管理，理解sql隔离

注意:使用mapper代理方法开发，namespace有特殊重要的作用 -->

<mapper namespace="test">

<!-- 在映射文件中配置很多sql语句 -->

<!-- 需求:通过id查询用户表的记录 -->

<!-- 通过select执行数据库查询，

id:标示映射文件中的sql，成为Statement的id

将sql语句封装到mappedStatement对象中，所以将id称为statement的id,

parameterType:指定输入参数的类型，

#{}标示一个占位符,

#{id}其中id表示接收输入参数的名称，如果输入参数是简单类型，那么#{}中的值可以任意(如value)。

resultType：指定sql输出结果的映射的java对象类型，

select指定resultType表示将单条记录映射成java对象-->

<select id="findUserById" parameterType="int" resultType="cn.edu.hpu.ssm.po.User">

SELECT * FROM USER WHERE id=#{id}

</select>

</mapper>

在SqlMapconfig.xml中加载User.xml

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<!-- 加载映射文件 -->

<mappers>

<!-- 通过resource方法一次加载一个映射文件 -->

<mapper resource="sqlmap/User.xml"/>

<!-- 批量加载mapper-->

<package name="cn.edu.hpu.ssm.mapper"/>

</mappers>

4.2dao(实现类继承SqlSessionDaoSupport)

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

4.3配置dao

首先创建UserDao接口和UserDaoImpl接口实现

UserDao.java:

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package cn.edu.hpu.ssm.dao;

import cn.edu.hpu.ssm.po.User;

//用户管理的Dao接口

public interface UserDao{

//根据Id查询用户信息

public User findUserById(int id) throws Exception;

}

UserDaoImpl.java:

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package cn.edu.hpu.ssm.dao;

import org.apache.ibatis.session.SqlSession;

import org.apache.ibatis.session.SqlSessionFactory;

import cn.edu.hpu.ssm.po.User;

public class UserDaoImpl implements UserDao{

//需要向dao实现类中注入SqlSessionFactory工厂

//这里我们暂时没用spring，我们通过构造方法注入

private SqlSessionFactory sqlSessionFactory;

public UserDaoImpl(SqlSessionFactory sqlSessionFactory){

this.sqlSessionFactory=sqlSessionFactory;

}

public User findUserById(int id) throws Exception {

SqlSession sqlSession=sqlSessionFactory.openSession();

User user=sqlSession.selectOne("test.findUserById",id);

//释放资源

sqlSession.close();

return user;

}

}

在applicationContext.xml中配置dao。

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<?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: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>

<!-- 原始Dao接口 -->

<bean id="userDao" class="cn.edu.hpu.ssm.dao.UserDaoImpl">

<property name="sqlSessionFactory" ref="sqlSessionFactory"></property>

</bean>

</beans>

让UserDaoImpl去继承SqlSessionDaoSupport类，在SqlSessionDaoSupport类中提供了set和getsqlSessionFactory的方法。

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package cn.edu.hpu.ssm.dao;

import org.apache.ibatis.session.SqlSession;

import org.mybatis.spring.support.SqlSessionDaoSupport;

import cn.edu.hpu.ssm.po.User;

public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao{

public User findUserById(int id) throws Exception {

//继承SqlSessionDaoSupport类，通过this.getSqlSession()得到sqlSession

SqlSession sqlSession=this.getSqlSession();

User user=sqlSession.selectOne("test.findUserById",id);

return user;

}

}

4.4测试程序

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package cn.edu.hpu.ssm.test;

import org.junit.Before;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import cn.edu.hpu.ssm.dao.UserDao;

import cn.edu.hpu.ssm.po.User;

public class UserDaoImplTest {

private ApplicationContext applicationContext;

//注解Before是在执行本类所有测试方法之前先调用这个方法

@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");

//调用UserDao的方法

User user=userDao.findUserById(1);

//输出用户信息

System.out.println(user.getId()+":"+user.getUsername());

}

}

测试结果和输出日志:

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DEBUG [main] - Creating a new SqlSession

DEBUG [main] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@8dcd5d] was not registered for synchronization because synchronization is not active

DEBUG [main] - Fetching JDBC Connection from DataSource

DEBUG [main] - JDBC Connection [jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8, UserName=root@localhost, MySQL-AB JDBC Driver] will not be managed by Spring

DEBUG [main] - ==> Preparing: SELECT * FROM USER WHERE id=?

DEBUG [main] - ==> Parameters: 1(Integer)

DEBUG [main] - <== Total: 1

DEBUG [main] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@8dcd5d]

DEBUG [main] - Returning JDBC Connection to DataSource

1:张明明

5.mapper代理开发

5.1mapper.xml和mapper.java

UserMapper.xml:

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<?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.edu.hpu.ssm.mapper.UserMapper">

<select id="findUserById" parameterType="int" resultType="cn.edu.hpu.mybatis.po.User">

SELECT * FROM USER WHERE id=#{id}

</select>

</mapper>

UserMapper.java:

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package cn.edu.hpu.ssm.mapper;

import cn.edu.hpu.ssm.po.User;

//用户管理的Dao接口

public interface UserMapper {

//根据Id查询用户信息

public User findUserById(int id) throws Exception;

}

5.2通过MapperFactoryBean创建代理对象

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<!-- mapper配置

MapperFactoryBean根据mapper接口生成mapper代理对象-->

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

<!-- mapperInterface指定mapper接口 -->

<property name="mapperInterface" value="cn.edu.hpu.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。所以要通过MapperScannerConfigurer进行mapper扫描。

5.3通过MapperScannerConfigurer进行mapper扫描（建议使用）

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<!-- 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容器中注入

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="cn.edu.hpu.ssm.mapper"/>

<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>

</bean>

sqlMapperConfig.xml中的mapper扫描就可以不要了

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<!-- 加载映射文件 -->

<mappers>

<!-- 通过resource方法一次加载一个映射文件 -->

<mapper resource="sqlmap/User.xml"/>

<!-- 批量加载mapper

和spring整合后，使用mapper扫描器，这里不需要配置了-->

<!--<package name="cn.edu.hpu.ssm.mapper"/>-->

</mappers>

5.4测试代码

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package cn.edu.hpu.ssm.test;

import org.junit.Before;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import cn.edu.hpu.ssm.mapper.UserMapper;

import cn.edu.hpu.ssm.po.User;

public class UserMapperTest {

private ApplicationContext applicationContext;

//注解Before是在执行本类所有测试方法之前先调用这个方法

@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.getId()+":"+user.getUsername());

}

}

测试结果及输出日志：

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DEBUG [main] - Returning cached instance of singleton bean 'userMapper'

DEBUG [main] - Creating a new SqlSession

DEBUG [main] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@13b5a3a] was not registered for synchronization because synchronization is not active

DEBUG [main] - Fetching JDBC Connection from DataSource

DEBUG [main] - JDBC Connection [jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8, UserName=root@localhost, MySQL-AB JDBC Driver] will not be managed by Spring

DEBUG [main] - ==> Preparing: SELECT * FROM USER WHERE id=?

DEBUG [main] - ==> Parameters: 1(Integer)

DEBUG [main] - <== Total: 1

DEBUG [main] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@13b5a3a]

DEBUG [main] - Returning JDBC Connection to DataSource

1:张明明