Question

我有一个标准的Java ThreadPoolExecutor线程，需要执行事务性的Spring JPA数据库交互。

虽然我发现如何为允许我执行某些JPA交互的线程设置实体管理器，但这并不能正确支持事务：

EntityManager entityManager = entityManagerFactory.createEntityManager();
EntityManagerHolder holder = new EntityManagerHolder(entityManager);
TransactionSynchronizationManager.bindResource(entityManagerFactory, holder);

一旦我尝试对数据库执行实际（删除）查询，就没有可用的有效事务：

org.springframework.dao.InvalidDataAccessApiUsageException: No EntityManager with actual transaction available for current thread - cannot reliably process 'remove' call; nested exception is javax.persistence.TransactionRequiredException: No EntityManager with actual transaction available for current thread - cannot reliably process 'remove' call
    at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:413) ~[spring-orm-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:246) ~[spring-orm-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:491) ~[spring-orm-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:59) ~[spring-tx-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213) ~[spring-tx-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:147) ~[spring-tx-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133) ~[spring-data-jpa-1.10.2.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) ~[spring-aop-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at com.sun.proxy.$Proxy98.deleteById(Unknown Source) ~[na:na]
    ...
Caused by: javax.persistence.TransactionRequiredException: No EntityManager with actual transaction available for current thread - cannot reliably process 'remove' call
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:282) ~[spring-orm-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at com.sun.proxy.$Proxy96.remove(Unknown Source) ~[na:na]
    at org.springframework.data.jpa.repository.query.JpaQueryExecution$DeleteExecution.doExecute(JpaQueryExecution.java:274) ~[spring-data-jpa-1.10.2.RELEASE.jar:na]
    at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:78) ~[spring-data-jpa-1.10.2.RELEASE.jar:na]
    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:102) ~[spring-data-jpa-1.10.2.RELEASE.jar:na]
    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:92) ~[spring-data-jpa-1.10.2.RELEASE.jar:na]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:482) ~[spring-data-commons-1.12.2.RELEASE.jar:na]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:460) ~[spring-data-commons-1.12.2.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:61) ~[spring-data-commons-1.12.2.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99) ~[spring-tx-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:280) ~[spring-tx-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) ~[spring-tx-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136) ~[spring-tx-4.3.2.RELEASE.jar:4.3.2.RELEASE]

如何从普通Java线程成功执行事务JPA查询，我将如何创建上下文（并在之后将其拆除）？

Answer 1

If you are using a dependency injection container, like Spring, you can use the @Transactional annotation on the method or class in which you call remove on the entity manager. This will ensure that every call in the stack trace will happen inside the transaction and also, if an exception is thrown all the changes in current transaction will be rolled back.

If you are not using Spring you will have to handle opening and closing the transaction yourself. Here is how you can do that:

   UserTransaction transaction = entityManager.getTransaction(); 

try { 
    transaction.begin(); 
    transaction.commit(); 
} catch(Exception ex) { 
    transaction.rollback(); 
    throw ex; 
}

Read this for more details Hope it helps

用于普通Java线程的程序化Spring JPA数据库访问上下文

1 个答案: