SpringData 学习（5）—— 使用 @Modifying 注解完成修改操作

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以上我们做的都是查询，那要如何实现修改、删除和添加呢？
可以通过以下两种方式：
（1）通过实现 CrudRepository 接口来完成（以后介绍）；
（2）通过 @Modifying 注解完成修改操作（注意：不支持新增）

我们依然使用 @Query 注解，但是还要附加注解 @Modifying。

@Modifying@Query("update Person set email = :email where lastName =:lastName")void updatePersonEmailByLastName(@Param("lastName")String lastName,@Param("email")String email);

测试方法很简单了，暂时并不粘贴出来，因为后面我们要改的。
控制台报错：

org.springframework.dao.InvalidDataAccessApiUsageException: Executing an update/delete query; nested exception is javax.persistence.TransactionRequiredException: Executing an update/delete query    at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:410)    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:216)    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:417)    at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:59)    at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:147)    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)    at org.springframework.data.jpa.repository.support.LockModeRepositoryPostProcessor$LockModePopulatingMethodIntercceptor.invoke(LockModeRepositoryPostProcessor.java:92)    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)    at com.sun.proxy.$Proxy29.updatePersonEmailByLastName(Unknown Source)    at com.liwei.springdata.service.PersonService.updateEmailByLastName(PersonService.java:15)    at com.liwei.springdata.test.DataSourceTest.testUsingModifingAnnotation(DataSourceTest.java:154)    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:497)    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:670)    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)Caused by: javax.persistence.TransactionRequiredException: Executing an update/delete query    at org.hibernate.jpa.spi.AbstractQueryImpl.executeUpdate(AbstractQueryImpl.java:71)    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)    at java.lang.reflect.Method.invoke(Method.java:497)    at org.springframework.orm.jpa.SharedEntityManagerCreator$DeferredQueryInvocationHandler.invoke(SharedEntityManagerCreator.java:362)    at com.sun.proxy.$Proxy31.executeUpdate(Unknown Source)    at org.springframework.data.jpa.repository.query.JpaQueryExecution$ModifyingExecution.doExecute(JpaQueryExecution.java:174)    at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:61)    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:95)    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:85)    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:323)    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)    ... 32 more

关键看这行 Caused by: javax.persistence.TransactionRequiredException: Executing an update/delete query，说明我们缺少事务配置。
于是
1、在 Spring 核心配置文件里引入事务管理器（这一步我们之前已经做了）

<context:component-scan base-package="com.liwei.springdata.service"></context:component-scan>

2、写好 Service 类的相关方法，在事务方法前面加上 @Transactional 注解。

@Servicepublic class PersonService {    @Autowired    private PersonRepository personRepository;    @Transactional    public void updateEmailByLastName(String lastName,String email){        personRepository.updatePersonEmailByLastName(lastName, email);    }}

测试代码：

// 以上都是查询，现在我们要测试修改@Testpublic void testUsingModifingAnnotation(){    personService.updateEmailByLastName("liwei", "121088825@qq.com");}

控制台打印：

这里写图片描述

经过测试，通过上面的方式实现删除也是可以得，代码我就不贴出来了，大家可以具体尝试一下，很简单。
这里写图片描述

总结：
（1）可以通过自定义的 JPQL 完成 UPDATE 和 DELETE 操作。注意： JPQL 不支持使用 INSERT；
（2）在 @Query 注解中编写 JPQL 语句，但必须使用 @Modifying 进行修饰. 以通知 SpringData，这是一个 UPDATE 或 DELETE 操作
（3）UPDATE 或 DELETE 操作需要使用事务，此时需要定义 Service 层，在 Service 层的方法上添加事务操作；
（4）默认情况下， SpringData 的每个方法上有事务，但都是一个只读事务。他们不能完成修改操作。

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