ConCurrent包下工具类-CyclicBarrier

需要一组线程同时达到某个条件后一起啊开始执行。
类似的场景：一个线程代表一个跑步运动员，当所有的运动员都准备好了之后才一起出发。只要有一个没有准备好，大家都继续等待。

    package com.lihuan.concurrentUtil;import java.util.Random;import java.util.concurrent.CyclicBarrier;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;public class CyclicBarrierTest {    static class MyRunnable implements Runnable{        private CyclicBarrier barrier;        private String name;        public MyRunnable(CyclicBarrier barrier, String name) {            this.barrier = barrier;            this.name = name;        }        @Override        public void run() {            try {                Thread.sleep(1000*(new Random().nextInt(5)));                System.out.println(name+"准备OK");                //每个线程执行await(）开始等待                barrier.await();            } catch (Exception e) {                e.printStackTrace();            }            System.out.println(name+"GO!!!");        }    }    public static void main(String[] args) {        //创建CyclicBarrier 设置屏障数为3        CyclicBarrier barrier = new CyclicBarrier(3);        /**         * 创建固定数量的线程池         * 添加三个线程         * 每个线程执行await(）开始等待         * 当三个线程都调用await(）时开始，一起开始执行         */        ExecutorService pool = Executors.newFixedThreadPool(3);        pool.execute(new Thread(new MyRunnable(barrier, "zhangsan")));        pool.execute(new Thread(new MyRunnable(barrier, "lisi")));        pool.execute(new Thread(new MyRunnable(barrier, "wangwu")));        pool.shutdown();    }}

结果