在Java 1.3中實現UncaughtExceptionHandler

Question

如何將在一個線程中拋出的異常傳遞給它的調用線程？

我必須使用Java版本1.3。 在Java 1.5中添加了Thread.UncaughtExceptionHandler 。

如果必須將代碼包裝在try塊中，並因此在導致異常的線程中捕獲異常，我感到非常高興。 我的問題是如何將這個異常傳遞給另一個線程。

謝謝！

Answer 1

可以通過synced，wait（）和notify（）將異常傳遞給調用線程。

class MyThread extends Thread implements Runnable {
  public Throwable exception; // a copy of any exceptions are stored here

  public void run() {
    try {
      throw new Exception("This is a test");
    }
    catch (Throwable e) {
      // An exception has been thrown.  Ensure we have exclusive access to
      // the exception variable
      synchronized(this) {
        exception = e; // Store the exception
        notify();      // Tell the calling thread that exception has been updated
      }
      return;
    }

    // No exception has been thrown        
    synchronized(this) {
      // Tell the calling thread that it can stop waiting
      notify();
    }
  }
} 

MyThread t = new MyThread();




t.start();
synchronized(t) {
  try {
    System.out.println("Waiting for thread...");
    t.wait();
    System.out.println("Finished waiting for thread.");
  }
  catch (Exception e) {
    fail("wait() resulted in an exception"); 
  }
  if (t.exception != null) {
    throw t.exception;
  }
  else {
    System.out.println("Thread completed without errors");
  }
}


try {
  System.out.println("Waiting to join thread...");
  t.join();
  System.out.println("Joined the thread");
}
catch (Exception e) {
  System.out.println("Failed to join thread");
}