9

我有一个Controller类和一个Monitor工作线程。控制器线程看起来像这样

public class ControllerA {
    public void ControllerA(){
        try{
            doWork();
        }
        catch(OhNoException e){
        //catch exception
        }

    public void doWork() throws OhNoException{

      new Thread(new Runnable(){
        public void run(){
        //Needs to monitor resources of ControllerA, 
        //if things go wrong, it needs to throw OhNoException for its parent
        }
        }).start();

      //do work here

    }
}

这样的设置可行吗？如何将异常抛出到线程外部？

4

2 回答 2

9

如何将异常抛出到线程外部？

有几种方法可以做到这一点。您可以UncaughtExceptionHandler在线程上设置 a ，也可以使用 anExecutorService.submit(Callable)并使用从Future.get().

最简单的方法是使用ExecutorService：

ExecutorService threadPool = Executors.newSingleThreadScheduledExecutor();
Future<Void> future = threadPool.submit(new Callable<Void>() {
      public Void call() throws Exception {
         // can throw OhNoException here
         return null;
     }
});
// you need to shut down the pool after submitting the last task
threadPool.shutdown();
try {
   // this waits for your background task to finish, it throws if the task threw
   future.get();
} catch (ExecutionException e) {
    // this is the exception thrown by the call() which could be a OhNoException
    Throwable cause = e.getCause();
     if (cause instanceof OhNoException) {
        throw (OhNoException)cause;
     } else if (cause instanceof RuntimeException) {
        throw (RuntimeException)cause;
     }
}

如果您想使用，UncaughtExceptionHandler那么您可以执行以下操作：

 Thread thread = new Thread(...);
 final AtomicReference throwableReference = new AtomicReference<Throwable>();
 thread.setUncaughtExceptionHandler(new UncaughtExceptionHandler() {
     public void uncaughtException(Thread t, Throwable e) {
         throwableReference.set(e);
     }
 });
 thread.start();
 thread.join();
 Throwable throwable = throwableReference.get();
 if (throwable != null) {
     if (throwable instanceof OhNoException) {
        throw (OhNoException)throwable;
     } else if (throwable instanceof RuntimeException) {
        throw (RuntimeException)throwable;
     }
 }
于 2012-10-15T13:56:39.343 回答
2

Runnable 接口不能抛出检查异常或返回值。在 Callable 接口中，您可以调用任何返回值或抛出异常的工作方法。监视器的主要任务是

  1. 使用可调用实例声明和初始化未来。

  2. 一个 getResult() 方法，它可以有一个return future.get();语句，并且应该在其 throws 子句中声明任何已检查的异常，以便由调用代码处理。这样我们就不必返回一个空值。

于 2012-10-15T17:40:29.933 回答