Java JUC工具类--CountDownLatch

• CountDownLatch：用于监听某些初始化操作，并且线程进行阻塞，等初始化执行完毕后，通知主线程继续工作执行

package com.example.core.juc;

import java.util.concurrent.CountDownLatch;

public class UseCountDownLatch {
    public static void main(String[] args) {
        CountDownLatch countDownLatch = new CountDownLatch(2);//需要两次唤醒
        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println("进入t1线程");
                try{
                    Thread.sleep(3000);//做一些初始化准备
                }catch(InterruptedException e){
                    e.printStackTrace();
                }
                System.out.println("t1线程初始化完毕，通知t3线程继续操作");
                countDownLatch.countDown();//通知t3
            }
        },"t1");

        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println("进入t2线程");
                try{
                    Thread.sleep(3000);//做一些初始化准备
                }catch(InterruptedException e){
                    e.printStackTrace();
                }
                System.out.println("t2线程初始化完毕，通知t3线程继续操作");
                countDownLatch.countDown();//通知t3
            }
        },"t2");

        Thread t3 = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println("进入t3线程,进入等待阶段");
                try{
                    countDownLatch.await();//等待阶段，需要唤醒
                }catch(InterruptedException e){
                    e.printStackTrace();
                }
                System.out.println("t3线程 进行后续的操作");
            }
        },"t3");

        t1.start();
        t2.start();
        t3.start();
    }
}
/*
进入t1线程
进入t2线程
进入t3线程,进入等待阶段
t1线程初始化完毕，通知t3线程继续操作
t2线程初始化完毕，通知t3线程继续操作
t3线程 进行后续的操作
*/