弹簧数据CrudRepository与悲观锁

Question

我在用

• 弹簧启动1.4.2
• 春季数据JPA 1.10.5
• PostgreSQL 9.5数据库

我希望在我的Spring数据存储库中有一个带有悲观锁的findOne方法，它与已经提供的findOne方法是分开的。

在this answer之后，我写道：

public interface RegistrationRepository extends CrudRepository<Registration, Long> {
    @Lock(LockModeType.PESSIMISTIC_WRITE)
    @Query("select r from Registration r where r.id = ?1")
    Registration findOnePessimistic(Long id);
}

这几乎成功了。

不幸的是，这不会在实体管理器缓存中刷新我的实体的先前实例。我有两个并发请求更新我的注册状态。

• 第二个等待第一个提交的事务。
• 第二个是，而不是，它考虑了第一个更改。

从而破坏了行为。

知道为什么@Lock不立即刷新实体管理器吗？

更新

下面是请求的示例代码：

public interface RegistrationRepository extends CrudRepository<Registration, Long> {

    @Lock(LockModeType.PESSIMISTIC_WRITE)
    @Query("select r from registration_table r where r.id = ?1")
    Registration findOnePessimistic(Long id);

}

public void RegistrationService {

    @Transactional
    public void doSomething(long id){
        // Both threads read the same version of the data 
        Registration registrationQueriedTheFirstTime = registrationRepository.findOne(id);

        // First thread gets the lock, second thread waits for the first thread to have committed
        Registration registration = registrationRepository.findOnePessimistic(id);
        // I need this to have this statement, otherwise, registration.getStatus() contains the value not yet updated by the first thread
        entityManager.refresh(registration);

        registration.setStatus(newStatus);
        registrationRepository.save(registration);
    }
}

Answer 1

您需要使用Spring为您创建的Spring：

    @Transactional
    public void doSomething(long id){
        // Both threads read the same version of the data 
        Registration registrationQueriedTheFirstTime = registrationRepository.findOne(id);

        // First thread gets the lock, second thread waits for the first thread to have committed
        Registration registration = registrationRepository.findOnePessimistic(id);
        // I need this to have this statement, otherwise, registration.getStatus() contains the value not yet updated by the first thread
        entityManager.refresh(registration);

        EntityManager em = EntityManagerFactoryUtils.getTransactionalEntityManager(<Your entity manager factory>);
        em.refresh(registration);
        registration.setStatus(newStatus);
        registrationRepository.save(registration);
    }

}