是否有可能使用@Transactional来度量所有Spring管理事务的时间?

Question

我想用JpaTJpaTransactionManager/PlatformTransactionManager测量Spring管理的事务的时间，以检测长挂起的事务，并警告某些侦听器这种情况。

我可以在@Transactional方法上使用aspect，但由于事务传播，它不是检测确切事务何时开始或结束的好方法。

这将是一个很好的东西，像事务侦听器访问开始/结束事件和一些bean名称的对象开始事务或只是堆栈跟踪

Answer 1

在注释方法中使用TransactionSynchronizationManager:

TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronization(){
       long startTime;
       void beforeCommit() {
           startTime = System.nanoTime();
       }
       void afterCommit(){
           System.out.println("Transaction time: " + (System.nanoTime() - startTime));
       }
});

使用aspect跟踪所有事务:

 @Aspect
 class TransactionAspect extends TransactionSynchronizationAdapter {
   @Before("@annotation(org.springframework.transaction.annotation.Transactional)")
   public void registerTransactionSyncrhonization() {
       TransactionSynchronizationManager.registerSynchronization(this);
   }
   ThreadLocal<Long> startTime = new ThreadLocal<>();
   void beforeCommit() {
       startTime.set(System.nanoTime());
   }
   void afterCommit(){
       System.out.println("Transaction time: " + (System.nanoTime() - startTime.get()));
   }
}

Answer 2

您可以考虑实现一个实现ApplicationListener<E extends ApplicationEvent>并在其中执行度量的类。像这样:

@Component
public class TransactionListener implements ApplicationListener<Neo4jDataManipulationEvent> {
   private Long transactionStart;
   private static final Logger log = LoggerFactory.getLogger(TransactionListener.class);
    @Override
    public void onApplicationEvent(Neo4jDataManipulationEvent event) {
        if (event instanceof BeforeSaveEvent) {
            transactionStart = System.currentTimeMillis();
        }
        if (event instanceof AfterSaveEvent) {
            log.debug("Transaction time in ms: ", System.currentTimeMillis() - transactionStart);
            log.debug("Source: ", event.getSource());
        }
    }

对于JPA，您可以考虑实现类似的解决方案(根据本教程):

public class LogListener {
    private Long transactionStart;
    @PrePersist
    @PreUpdate
    @PreRemove
    private void before(Object object) {
        transactionStart = System.currentTimeMillis();
    }
    @PostPersist
    @PostUpdate
    @PostRemove
    private void after(Object object) {
        System.out.println("Transaction time in ms: ", System.currentTimeMillis() - transactionStart);
        System.out.println("Source: ", object.getClass());
    }
}

你需要用@EntityListeners(LogListener.class)在你的实体类中标注哪些实例被持久化到DB。