我仍处于 Spring 事务和 aop 的学习阶段,我有一些误解:
1. 如果我不使用 aop-advice,我会为每个服务指定如下内容:
@Transactional(rollbackFor=java.lang.Exception.class,readOnly=true)
然后我查看 spring 日志,一切似乎都按预期工作。我的意思是创建了一个事务,如果出现异常,我会得到回滚。但是如果你使用类似的东西:
<bean id="txManagerVA" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="emfVA" />
</bean>
<tx:annotation-driven transaction-manager="txManagerVA" />
<aop:config>
<aop:pointcut id="transactionalServiceMethodsVA" expression="execution(* xxx.services.vs.*.*(..))"/>
<aop:advisor advice-ref="txManagerVAAdvice" pointcut-ref="transactionalServiceMethodsVA"/>
</aop:config>
<tx:advice id="txManagerVAAdvice" transaction-manager="txManagerVA">
<tx:attributes>
<tx:method name="get*" rollback-for="java.lang.Exception" read-only="true"/>
<tx:method name="*" rollback-for="java.lang.Exception" />
</tx:attributes>
</tx:advice>
因此,当我使用这种场景查看 spring 日志时,似乎有 2 个事务在另一个内部,因为在回滚后我得到类似的东西:
(IntermedServiceImpl.java:45) - WE HAVE AN EXCEPTION !!!! nullCrocodilu
(TransactionAspectSupport.java:406) - Completing transaction for [xxx.IntermedServiceImpl.getIntermed] after exception: java.lang.Exception: Crocodilu
(RuleBasedTransactionAttribute.java:130) - Applying rules to determine whether transaction should rollback on java.lang.Exception: Crocodilu
(RuleBasedTransactionAttribute.java:147) - Winning rollback rule is: RollbackRuleAttribute with pattern [java.lang.Exception]
(AbstractPlatformTransactionManager.java:935) - Triggering beforeCompletion synchronization
(TransactionSynchronizationManager.java:243) - Removed value [org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerSynchronization@63fd1f47] for key [org.hibernate.ejb.EntityManagerImpl@4eb35bed] from thread [thread-pool-1-8080(6)]
(AbstractPlatformTransactionManager.java:843) - Initiating transaction rollback
//SO FAR SO GOOD
(JpaTransactionManager.java:533) - Rolling back JPA transaction on EntityManager [org.hibernate.ejb.EntityManagerImpl@b3fbd77]
(AbstractPlatformTransactionManager.java:964) - Triggering afterCompletion synchronization
(TransactionSynchronizationManager.java:331) - Clearing transaction synchronization
(TransactionSynchronizationManager.java:243) - Removed value [org.springframework.orm.jpa.EntityManagerHolder@45a27493] for key [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean@7ed30037] from thread [thread-pool-1-8080(6)]
(JpaTransactionManager.java:593) - Closing JPA EntityManager [org.hibernate.ejb.EntityManagerImpl@b3fbd77] after transaction
(EntityManagerFactoryUtils.java:343) - Closing JPA EntityManager
--> (AbstractPlatformTransactionManager.java:1012) - Resuming suspended transaction after completion of inner transaction <--
(TransactionSynchronizationManager.java:272) - Initializing transaction synchronization
(TransactionAspectSupport.java:406) - Completing transaction for [xxx.IntermedServiceImpl.getIntermed] after exception: java.lang.Exception: Crocodilu
(RuleBasedTransactionAttribute.java:130) - Applying rules to determine whether transaction should rollback on java.lang.Exception: Crocodilu
(RuleBasedTransactionAttribute.java:147) - Winning rollback rule is: null
(RuleBasedTransactionAttribute.java:152) - No relevant rollback rule found: applying default rules
(AbstractPlatformTransactionManager.java:922) - Triggering beforeCommit synchronization
(AbstractPlatformTransactionManager.java:935) - Triggering beforeCompletion synchronization
(AbstractPlatformTransactionManager.java:752) - Initiating transaction commit
(JpaTransactionManager.java:507) - Committing JPA transaction on EntityManager [org.hibernate.ejb.EntityManagerImpl@405c9cef]
(AbstractPlatformTransactionManager.java:948) - Triggering afterCommit synchronization
(AbstractPlatformTransactionManager.java:964) - Triggering afterCompletion synchronization
(TransactionSynchronizationManager.java:331) - Clearing transaction synchronization
(TransactionSynchronizationManager.java:243) - Removed value [org.springframework.orm.jpa.EntityManagerHolder@1f0cf366] for key [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean@6012b597] from thread [thread-pool-1-8080(6)]
(JpaTransactionManager.java:593) - Closing JPA EntityManager [org.hibernate.ejb.EntityManagerImpl@405c9cef] after transaction
(EntityManagerFactoryUtils.java:343) - Closing JPA EntityManager
如您所见,我已经标记了我不理解的行。
第二个问题:在同一个日志文件中,我注意到如下一行:
(JpaTransactionManager.java:407) - Not exposing JPA transaction [org.hibernate.ejb.EntityManagerImpl@b3fbd77] as JDBC transaction because JpaDialect [org.springframework.orm.jpa.DefaultJpaDialect@77acf1c0] does not support JDBC Connection retrieval
我用谷歌搜索了一下,然后添加了这个:
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="databasePlatform" value="org.hibernate.dialect.MySQL5InnoDBDialect" />
</bean>
</property>
entitymanager bean,现在看来 jpa 将事务公开给 jdbc 事务。问题是我不知道这种配置的优点/缺点是什么。