如何安全地终止线程？

1、废弃的stop()方法

stop()方法在终结一个线程时不会保证线程的资源正常释放，通常是没有给予线程完成资源释放工作的机会，因此会导致程序可能工作在不确定状态下。

2、通过标识位或中断操作

import java.util.concurrent.TimeUnit;

public class ShutDown {
    public static void main(String[] args) throws InterruptedException {
        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能够感知中断而结束
        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Runner two进行取消，使CountThread能够感知on为false而结束
        TimeUnit.SECONDS.sleep(1);
        two.cancel();
    }

    static class Runner implements Runnable{
        private long i;
        private volatile boolean on = true;

        @Override
        public void run() {
            while (on && !Thread.currentThread().isInterrupted()){
                i++;
            }
            System.out.println("Count i = " + i);
        }
　　　　// 标识位置为false
        public void cancel(){
            on = false;
        }
    }
}