如何从线程中捕获异常

问题描述

我有 Java 主类，在该类中，我启动了一个新线程，在主类中，它一直等到线程死亡.在某个时刻，我从线程抛出了一个运行时异常，但我无法在主类中捕获从线程抛出的异常.

I have Java main class, in the class, I start a new thread, in the main, it waits until the thread dies. At some moment, I throw a runtime exception from the thread, but I can't catch the exception thrown from the thread in the main class.

代码如下:

public class Test extends Thread
{
  public static void main(String[] args) throws InterruptedException
  {
    Test t = new Test();

    try
    {
      t.start();
      t.join();
    }
    catch(RuntimeException e)
    {
      System.out.println("** RuntimeException from main");
    }

    System.out.println("Main stoped");
  }

  @Override
  public void run()
  {
    try
    {
      while(true)
      {
        System.out.println("** Started");

        sleep(2000);

        throw new RuntimeException("exception from thread");
      }
    }
    catch (RuntimeException e)
    {
      System.out.println("** RuntimeException from thread");

      throw e;
    }
    catch (InterruptedException e)
    {

    }
  }
}

有人知道为什么吗?

推荐答案

使用 Thread.UncaughtExceptionHandler.

Thread.UncaughtExceptionHandler h = new Thread.UncaughtExceptionHandler() {
    @Override
    public void uncaughtException(Thread th, Throwable ex) {
        System.out.println("Uncaught exception: " + ex);
    }
};
Thread t = new Thread() {
    @Override
    public void run() {
        System.out.println("Sleeping ...");
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            System.out.println("Interrupted.");
        }
        System.out.println("Throwing exception ...");
        throw new RuntimeException();
    }
};
t.setUncaughtExceptionHandler(h);
t.start();

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