mybatis学习笔记(17)-spring和mybatis整合

标签： mybatis springmvc

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本文主要将如何将spring和mybatis整合，只是作简单的示例，没有使用Maven构建。并展示mybatis与spring整合后如何进行原始dao开发和mapper代理开发。

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

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。

sqlSessionFactory

在applicationContext.xml配置sqlSessionFactory和数据源

sqlSessionFactory在mybatis和spring的整合包下。

原始dao开发(和spring整合后)

• User.xml

    
    
        
         
         
         
             SELECT * FROM  user  WHERE id=#{value}    
    

在SqlMapconfig.xml中加载User.xml

• dao(实现类继承SqlSessionDaoSupport)

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

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;    }}

• 配置dao

在applicationContext.xml中配置dao

• 测试程序

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 {		// 创建UserDao的对象		UserDao userDao = (UserDao)applicationContext.getBean("userDao");		// 调用UserDao的方法		User user = userDao.findUserById(1);				System.out.println(user);	}}

mapper代理开发

• mapper.java

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

• mapper.xml

    
    
        
         
             SELECT * FROM  user  WHERE id=#{value}    
    

• 通过MapperFactoryBean创建代理对象

    
    
             //mapperInterface指定mapper接口        
             
     
    

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（建议使用）

• 测试代码

package com.iot.mybatis.mapper;import com.iot.ssm.mapper.UserMapper;import com.iot.ssm.po.User;import org.junit.Before;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;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");		//调用userMapper的方法		User user = userMapper.findUserById(1);		System.out.println(user);	}}

遇到的问题

org.springframework.beans.factory.BeanDefinitionStoreException: Failed to read candidate component class: file [D:\intellij\workspace\spring-mybatis\out\production\spring-mybatis\com\iot\ssm\mapper\UserMapper.class]; nested exception is java.lang.IllegalArgumentException	at 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.
    
     (ClassPathXmlApplicationContext.java:139)	at org.springframework.context.support.ClassPathXmlApplicationContext.
     
      (ClassPathXmlApplicationContext.java:83)	at com.iot.mybatis.mapper.UserMapperTest.setUp(UserMapperTest.java:17)	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)	at java.lang.reflect.Method.invoke(Method.java:483)	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.junit.runner.JUnitCore.run(JUnitCore.java:157)	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234)	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74)	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)	at java.lang.reflect.Method.invoke(Method.java:483)	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)Caused by: java.lang.IllegalArgumentException	at org.springframework.asm.ClassReader.
      
       (Unknown Source)	at org.springframework.asm.ClassReader.
       
        (Unknown Source)	at org.springframework.asm.ClassReader.
        
         (Unknown Source)	at org.springframework.core.type.classreading.SimpleMetadataReader.
         
          (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) ... 35 more
         
        
       
      
     
    

• 搜到的答案

总结起来就是java 8 和spring 3 不能一起用，我在IDEA的project settings里把project language level换成7就好了。具体原因还不清楚

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