Mybatis学习笔记（十四）——mybatis与spring整合

学习笔记（十四）——mybatis与spring整合"/>

Mybatis学习笔记（十四）——mybatis与spring整合

本博客源码下载：戳我一下

Mybatis学习笔记汇总：戳我一下

一、与spring整合

实现mybatis与spring进行整合，通过spring管理SqlSessionFactory、mapper接口。

二、导入jar包

mybatis官方提供的mybatis与spring整合jar包：

还包括其它jar包：

• spring3.2.0
• mybatis3.2.7
• dbcp连接池
• 数据库驱动

三、Mybatis配置文件

在classpath下创建mybatis/SqlMapConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis//DTD Config 3.0//EN"
".dtd">
<configuration><!-- 别名的定义 --><typeAliases><package name="com.jiayifan.ssm.po"/></typeAliases><!-- 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 指定mapper接口的包名，mybatis自动的扫描包下的所有mapper接口并加载，但是必须遵循 “通过mapper接口加载单个映射文件”的规范--><package name="com.jiayifan.ssm.mapper"/></mappers>
</configuration>

四、Spring配置文件：

在classpath下创建spring/applicationContext.xml，定义数据库链接池、SqlSessionFactory。

<beans xmlns=""xmlns:xsi="" xmlns:mvc=""xmlns:context=""xmlns:aop="" xmlns:tx=""xsi:schemaLocation=" .2.xsd  .2.xsd  .2.xsd  .2.xsd  .2.xsd "><!-- 加载配置文件 --><context:property-placeholder location="classpath:db.properties"/><!-- 数据库连接池 --><bean id="dataSource" class="org.apachemons.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> <!-- mapper配置 --><!-- 让spring管理sqlsessionfactory 使用mybatis和spring整合包中的 --><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><!-- 加载mybatis的全局配置文件 --><property name="configLocation" value="mybatis/SqlMapConfig.xml" /><!-- 数据库连接池 --><property name="dataSource" ref="dataSource" /></bean>
</beans>

五、原始DAO开发

1、编写User.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis//DTD Mapper 3.0//EN"
".dtd">
<!-- namespace命名空间，作用是对sql进行分类化管理
注意：如果使用mapper代理方法开发，namespace有特殊的作用-->
<mapper namespace="test"><select id="findUserById" parameterType="int"resultType="com.jiayifan.ssm.po.User">SELECT * FROM USER WHERE id=#{id}</select>
</mapper>

2、编写DAO和DAO实现类(实现类继承SqlSessionDaoSupport)
DAO接口：

package com.jiayifan.ssm.dao;import com.jiayifan.ssm.po.User;/*** dao接口，用户管理* @author 贾一帆**/
public interface UserDao {//根据ID查询用户信息public User findUserById(int id) throws Exception;
}

DAO实现类：

package com.jiayifan.ssm.dao;import java.util.Date;import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.support.SqlSessionDaoSupport;import com.jiayifan.ssm.po.User;/*** dao接口实现类* @author 贾一帆**/
public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao {@Overridepublic User findUserById(int id) throws Exception {SqlSession sqlSession = this.getSqlSession();User user = sqlSession.selectOne("test.findUserById",id);return user;}
}

3、配置DAO
在applicationContext.xml中配置dao。

<bean id="userDao" class="com.jiayifan.ssm.dao.UserDaoImpl"><property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
</bean>

4、测试程序

package com.jiayifan.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 com.jiayifan.ssm.po.User;public class UserDaoImplTest {private ApplicationContext applicationContext;@Beforepublic void setUp() throws Exception {applicationContext = new ClassPathXmlApplicationContext("spring/applicationContext.xml");}@Testpublic void testFindUserById() throws Exception {UserDao userDao = (UserDao) applicationContext.getBean("userDao");User user = userDao.findUserById(1);System.out.println(user);}}

五、Mapper代理开发DAO（使用MapperFactoryBean创建代理对象）

1、UserMapper接口

package com.jiayifan.ssm.mapper;import java.util.List;import com.jiayifan.ssm.po.User;/*** mapper接口* @author 贾一帆**/
public interface UserMapper {//根据ID查询用户信息public User findUserById(int id) throws Exception;}

2、UserMapper配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis//DTD Mapper 3.0//EN"
".dtd">
<!-- namespace命名空间，作用是对sql进行分类化管理
注意：如果使用mapper代理方法开发，namespace有特殊的作用,namespace等于mapper接口地址-->
<mapper namespace="com.jiayifan.ssm.mapper.UserMapper"><select id="findUserById" parameterType="int"resultType="com.jiayifan.ssm.po.User">SELECT * FROM USER WHERE id=#{id}</select></mapper>

3、使用Spring创建Mapper对象

<!-- mapper配置MapperFactoryBean：可以根据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.jiayifan.ssm.mapper.UserMapper"></property><property name="sqlSessionFactory" ref="sqlSessionFactory"></property></bean>

4、测试代码`

    @Beforepublic void setUp() throws Exception {applicationContext = new ClassPathXmlApplicationContext("spring/applicationContext.xml");}@Testpublic void testFindUserById() throws Exception {UserMapper userMapper = (UserMapper) applicationContext.getBean("userMapper");User user = userMapper.findUserById(1);System.out.println(user);}

5、此方法的问题
需要针对每个mapper进行配置，麻烦。

六、Mapper代理开发DAO（使用MapperScannerConfigurer进行mapper扫描）

这里只是把applicationContext.xml配置文件修改一下

    <!-- mapper配置MapperFactoryBean：可以根据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.jiayifan.ssm.mapper.UserMapper"></property><property name="sqlSessionFactory" ref="sqlSessionFactory"></property></bean> --><!-- mapper的批量扫描 从mapper的包中扫描出mapper接口，自动的创建代理对象并在spring容器中注册遵循一些规范：需要将mapper接口的类名和mapper.xml映射文件名保持一致且在一个目录中。--><bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"><!-- 指定扫描的包名如果扫描多个包，每个包名中间用半角逗号隔开--><property name="basePackage" value="com.jiayifan.ssm.mapper"></property><property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property></bean>

测试代码不变，注意如果你使用的jdk是jdk1.8版本，而spring是3.0版本，会出现下面这样的bug

org.springframework.beans.factory.BeanDefinitionStoreException: Failed to read candidate component class: file [I:\java\MybatisAndSpring\bin\com\jiayifan\ssm\mapper\UserMapper.class]; nested exception is java.lang.IllegalArgumentExceptionat org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider.findCandidateComponents(ClassPathScanningCandidateComponentProvider.java:281)at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.doScan(ClassPathBeanDefinitionScanner.java:242)at org.mybatis.spring.mapper.ClassPathMapperScanner.doScan(ClassPathMapperScanner.java:155)at org.springframework.context.annotation.ClassPathBeanDefinitionScanner.scan(ClassPathBeanDefinitionScanner.java:220)at org.mybatis.spring.mapper.MapperScannerConfigurer.postProcessBeanDefinitionRegistry(MapperScannerConfigurer.java:315)at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:630)at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:461)at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)at com.jiayifan.ssm.mapper.UserMapperTest.setUp(UserMapperTest.java:17)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)at java.lang.reflect.Method.invoke(Unknown Source)at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27)at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:69)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:48)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)at org.junit.runners.ParentRunner.run(ParentRunner.java:292)at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Caused by: java.lang.IllegalArgumentExceptionat org.springframework.asm.ClassReader.<init>(Unknown Source)at org.springframework.asm.ClassReader.<init>(Unknown Source)at org.springframework.asm.ClassReader.<init>(Unknown Source)at org.springframework.core.type.classreading.SimpleMetadataReader.<init>(SimpleMetadataReader.java:52)at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:80)at org.springframework.core.type.classreading.CachingMetadataReaderFactory.getMetadataReader(CachingMetadataReaderFactory.java:101)at org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider.findCandidateComponents(ClassPathScanningCandidateComponentProvider.java:257)... 32 more

这里只需要把jdk降为1.7版本就可以了，或者把spring升级一下。