AQS(2)-CountDownlanch

CountDownlanch:将线程陷入等待状态,直到其count为0才开始执行

代码示例:

package com.hzh.countdownlanch;

import java.util.concurrent.CountDownLatch;

/*
*
* 同步工具类,让一个线程一直处于等待状态
*
* */
public class CountDownLanchDemo implements Runnable {

    /*1存储在state*/
    static CountDownLatch countDownLatch = new CountDownLatch(1);

    public static void main(String[] args) {


        for (int i = 0; i < 1000; i++) {

            new Thread(new CountDownLanchDemo()).start();


        }

        countDownLatch.countDown();

    }

    @Override
    public void run() {

        try {

            countDownLatch.await();

            /*使用场景:例如此时1000个线程都陷入等待状态,主线程中执行countDown才会触发后面的代码

            * 当使用异步连接服务器时,可以当服务器返回连接成功的时候才执行后面的代码
            * */

            System.out.println(Thread.currentThread().getName());

        } catch (Exception e) {

            e.printStackTrace();

        }

    }
}