安全终止线程

中断操作是一种简便的线程间交互的方式，这种交互方式最适合用来取消或者停止任务。除了中断外，还能利用一个boolean变量来控制是否需要停止并终止该线程。例如：

class Termination{
    public static void main(String[] args) throws Exception{
        Runner one = new Runner();
        Thread countThread = new Thread(one, "countThread");
        countThread.start();
        //睡眠1秒，main线程对countThread进行中断，使countThread能够感知中断结束
        TimeUnit.SECONDS.sleep(1);
        countThread.interrupt();
        Runner two = new Runner();
        countThread = new Thread(two, "countThread");
        countThread.start();
        //睡眠1秒，main线程对two进行取消，使countThread能够感知on为false而结束
        TimeUnit.SECONDS.sleep(1);
        two.cancel();
    }
    private static class Runner implements Runnable{
        private Long count = 0L;
        private volatile boolean on = true;
        @Override
        public void run(){
            while (on && !Thread.currentThread().isInterrupted()){
                count++;
            }
            System.out.println("count =  " + count);
        }
        public void cancel(){
            on = false;
        }
    }
}