Jax-ws @PreDestroy 它什么时候被准确调用？

发布于 2024-11-02 06:23:24 字数 526 浏览 1 评论 0原文

我有一个使用 @PostConstruct 和 @PreDestory 注释的简单 Web 服务。

@PostConstruct
private void init() {...} //initialize some database connection

@PreDestroy
private void release() {...} //release data base resources

然后客户端会调用一些web方法来进行一些数据库操作。我通过在代码中设置断点进行了简单的测试。 @PostConstruct 工作正常。但@PreDestroy 方法永远不会被调用。

我认为当客户端完成调用 Web 方法时，@PreDestroy 总是会被调用，因为 Web 服务本质上是无状态的。所以最后，实例总是被销毁，在此之前，应该调用我的release方法？这是正确的理解吗？

但在阅读了一些在线资源后，我感到困惑。有人说 @PreDestroy 在未部署时会被调用？

原文

I have a simply web service using @PostConstruct and @PreDestory annotations.

@PostConstruct
private void init() {...} //initialize some database connection

@PreDestroy
private void release() {...} //release data base resources

then a client will call some web methods to do some database operations. I did a simply testing by setting break points in the code. The @PostConstruct works fine. but @PreDestroy method never get called.

I thought @PreDestroy will always get called when a client finish calling a web method since web service is stateless by nature. So in the end, the instance is always destroyed and before that, my release method should be called? Is this a correct understanding?

But after reading some online resources, i got confused. some says @PreDestroy will be called when it's un-deployed?

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苹果你个爱泡泡 2024-11-09 06:23:24

@PreDestroy 仅在应用程序服务器决定减小 Method-Ready 池的大小时调用 - 即它确定不需要保留尽可能多的 @WebService @Stateless 实例 会话 bean 周围。每次调用 @WebMethod 后不会调用它（并且仅当将新实例添加到 Method-ready 池中时才会调用 @PostConstruct，而不一定是在之前每个 Web 方法调用）。

如果您需要在每次方法调用之前和之后调用逻辑，您可以按如下方式执行：

@AroundInvoke
public Object intercept( InvocationContext ctx )
{
  try
  {
    init();
    return ctx.proceed();
  }
  finally
  {
    release();
  }
}

可以将此方法添加到您的 @WebService bean 中，或者使用 @Interceptors 作为单独的类添加代码>

@PreDestroy is only called when the application server decides to reduce the size of the Method-Ready pool - i.e. it determines it doesn't need to keep as many instances of your @WebService @Stateless session bean around. It doesn't get called after each invocation of your @WebMethod (and @PostConstruct is only called when a new instance is added to the Method-ready pool, not necessarily before each web method invocation).

If you have logic you need called before and after each method invocation you could do it as follows:

@AroundInvoke
public Object intercept( InvocationContext ctx )
{
  try
  {
    init();
    return ctx.proceed();
  }
  finally
  {
    release();
  }
}

This method can be added to your @WebService bean or as a separate class using @Interceptors

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