弹簧数据 Crud存储库和悲观锁

java spring spring-data spring-data-jpa

2022-09-01 14:47:42

我正在使用

弹簧靴 1.4.2
春季数据 JPA 1.10.5
PostgreSQL 9.5 database

我希望在我的Spring Data存储库中有一个具有悲观锁的方法，该方法与已经提供的方法分开。findOnefindOne

按照这个答案，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);
}

这几乎有效。

遗憾的是，这不会刷新实体管理器缓存中实体的上一个实例。我有两个并发请求更新我的注册状态

第二个等待第一个事务提交
第二个没有考虑第一个所做的更改。

因此，破碎的行为。

任何线索为什么不开箱即用地刷新实体管理器？@Lock

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);
    }
}

答案 1

您需要使用为您创建的：entityManger transactionSpring

    @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);
    }

}

答案 2