Java多线程之多线程异常捕捉

public class ThreadException implements Runnable{
  @Override
  public void run() {
    throw new RuntimeException();
  }
  //现象：控制台打印出异常信息，并运行一段时间后才停止
  public static void main(String[] args){
    //就算把线程的执行语句放到try-catch块中也无济于事
    try{
      ExecutorService exec = Executors.newCachedThreadPool();
      exec.execute(new ThreadException());
    }catch(RuntimeException e){
      System.out.println("Exception has been handled!");
    }
  }
}

/*
 * 第一步：定义符合线程异常处理器规范的“异常处理器”
 * 实现Thread.UncaughtExceptionHandler规范
 */
class MyUncaughtExceptionHandler implements Thread.UncaughtExceptionHandler{
  /*
   * Thread.UncaughtExceptionHandler.uncaughtException()会在线程因未捕获的异常而临近死亡时被调用
   */
  @Override
  public void uncaughtException(Thread t, Throwable e) {
    System.out.println("caught  "+e);
  }
}

/*
 * 第二步：定义线程工厂
 * 线程工厂用来将任务附着给线程，并给该线程绑定一个异常处理器
 */
class HanlderThreadFactory implements ThreadFactory{
  @Override
  public Thread newThread(Runnable r) {
    System.out.println(this+"creating new Thread");
    Thread t = new Thread(r);
    System.out.println("created "+t);
    t.setUncaughtExceptionHandler(new MyUncaughtExceptionHandler());//设定线程工厂的异常处理器
    System.out.println("eh="+t.getUncaughtExceptionHandler());
    return t;
  }
}

/*
 * 第三步：我们的任务可能会抛出异常
 * 显示的抛出一个exception
 */
class ExceptionThread implements Runnable{
  @Override
  public void run() {
    Thread t = Thread.currentThread();
    System.out.println("run() by "+t);
    System.out.println("eh = "+t.getUncaughtExceptionHandler());
    throw new RuntimeException();
  }
}

/*
 * 第四步：使用线程工厂创建线程池，并调用其execute方法
 */
public class ThreadExceptionUncaughtExceptionHandler{
  public static void main(String[] args){
    ExecutorService exec = Executors.newCachedThreadPool(new HanlderThreadFactory());
    exec.execute(new ExceptionThread());
  }
}

public static void main(String[] args){
    Thread.setDefaultUncaughtExceptionHandler(new MyUncaughtExceptionHandler());
    ExecutorService exec =Executors.newCachedThreadPool();
    exec.execute(new ExceptionThread());
}