线程的异常捕获(非线程组方式)

由于线程的种种特性,有时候我们不能捕获线程所抛出的异常,如下情况:

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class ExceptionThread implements Runnable{
	public void run() {
		throw new RuntimeException();
	}
	public static void main(String[] args) {
		ExecutorService executorService = Executors.newCachedThreadPool();
		try{
			executorService.execute(new ExceptionThread());
		}catch(RuntimeException e){
			System.out.println("RuntimeException!");
		}
	}
}

此代码运行,控制台显示:

Exception in thread "pool-1-thread-1" java.lang.RuntimeException
	at example.ExceptionThread.run(ExceptionThread.java:9)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)
	at java.lang.Thread.run(Thread.java:595)

当然,我们可以用线程组来捕获这些异常,不过Effiective Java的作者不提倡用线程组(认为线程组是个不成功的"尝试"),所以,如果是java1.5以上版本的话,我们可以用以下方法来捕获这个异常:

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class ExceptionThread implements Runnable {
	public void run() {
		throw new RuntimeException();
	}
	public static void main(String[] args) {
		Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
					public void uncaughtException(Thread t, Throwable e) {
						System.out.println("RuntimeException!");
					}
				});
		ExecutorService executorService = Executors.newCachedThreadPool();
		executorService.execute(new ExceptionThread());
		
	}
}

控制台输出:

RuntimeException!