java - Spring Boot 在关闭时关闭 hibernate session - 在 @Async 方法完成之前

Question

我有一个 Spring Boot 应用程序的问题，它在 @Async 之前关闭时关闭 EntityManager/session|任务(使用 EntityManager 的)已完成。

有 2 个类与此问题相关:

调度器

预定方法保留有限数量的作业并调用 @Async方法在 XYJobProcessor那做实际的工作。

@Component
public class XYJobProcessingTimer {

    private final XYJobService      xyJobService;
    private final XYJobProcessor    xyJobProcessor;

    //constructor skipped

    @Scheduled(initialDelayString = "${initial_delay}", fixedDelayString = "${delay}")
    public void performXYJobProcessing() {
        final String ticket = UUID.randomUUID().toString();
        final int reservedJobs = xyJobService.findAndReserveReadyXYJobs(ticket);

        if (reservedJobs > 0) {
            final Collection<XYJob> xyJobs = xyJobService.readReservedJobs(ticket);
            xyJobProcessor.process(xyJobs);
        }
    }

}

异步处理器

@Async 注释方法调用访问 EntityManager 的服务。

@Service
public class XYJobProcessor {

    private final XYJobService  xyJobService;

    // constructor skipped

    @Async("xyJobProcessorExecutor")
    public void process(final Collection<XYJob> jobs) {
        // This service uses the EntityManager and takes some time depending o job count.
        xyJobService.createXYJobsAndDelete(jobs);
    }

}

配置
Executor的配置运行 @Async任务。创建的线程是非守护进程。

@Configuration
public class AsyncExecutorConfiguration {

    @Bean(name = "xyJobProcessorExecutor")
    public Executor xyJobProcessorExecutor() {
        final SimpleAsyncTaskExecutor executor = new SimpleAsyncTaskExecutor();
        executor.setConcurrencyLimit(10);
        executor.setThreadNamePrefix("Hasselhoff-");
        return executor;
    }

}

问题

当我关闭应用程序时，spring 会立即关闭 EntityManager session - 在所有 @Async 之前任务已经完成。这导致以下异常:

2017-08-31 16:10:54.212 ERROR 12663 --- [Hasselhoff-12] .a.i.SimpleAsyncUncaughtExceptionHandler : Unexpected error occurred invoking async method 'public void de.xy.services.XYJobProcessor.process(java.util.Collection)'.org.springframework.orm.jpa.JpaSystemException: Session is closed!; nested exception is org.hibernate.SessionException: Session is closed!
        at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:333)
        at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:244)
        at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:521)
        at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:761)
        at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:730)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:504)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:292)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:673)
        at de.xy.services.XYJobService$$EnhancerBySpringCGLIB$$6b9cb1ae.createXYJobsAndDelete(<generated>)
        at de.xy.services.XYJobProcessor.process(XYJobProcessor.java:24)
        at de.xy.services.XYJobProcessor$$FastClassBySpringCGLIB$$ccc40c8f.invoke(<generated>)
        at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
        at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:738)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
        at org.springframework.aop.interceptor.AsyncExecutionInterceptor$1.call(AsyncExecutionInterceptor.java:115)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at org.springframework.core.task.SimpleAsyncTaskExecutor$ConcurrencyThrottlingRunnable.run(SimpleAsyncTaskExecutor.java:268)
        at java.lang.Thread.run(Thread.java:748)
Caused by: org.hibernate.SessionException: Session is closed!
        at org.hibernate.internal.AbstractSessionImpl.errorIfClosed(AbstractSessionImpl.java:132)
        at org.hibernate.internal.SessionImpl.getPersistenceContext(SessionImpl.java:2088)
        at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:340)
        at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39)
        at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1282)
        at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:465)
        at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:2963)
        at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2339)
        at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:485)
        at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:147)
        at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$100(JdbcResourceLocalTransactionCoordinatorImpl.java:38)
        at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:231)
        at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:65)
        at org.hibernate.jpa.internal.TransactionImpl.commit(TransactionImpl.java:61)
        at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:517)
        ... 17 common frames omitted

有没有办法让Spring等待@Async执行要在关闭 EntityManager 之前完成？或者这是一个错误？

Answer 1

感谢@M.Deinum，我发现了如何避免这个问题:

使用 ThreadPoolTaskExecutor (而不是 SimpleAsyncTaskExecutor )并将其设置为 awaitTerminationSeconds与 waitForTasksToCompleteOnShutdown 相结合的属性(property)设置为 true解决了我的问题。

来自 setAwaitTerminationSeconds 的 JavaDoc :

Set the maximum number of seconds that this executor is supposed to block on shutdown in order to wait for remaining tasks to complete their execution before the rest of the container continues to shut down. This is particularly useful if your remaining tasks are likely to need access to other resources that are also managed by the container.

这是我的问题的确切描述和解决方案。