多线程控制工具类--倒计时器CountDownLatch的使用（模仿火箭发射）

Posted 2020-10-21 java-spring

package com.thread.test.Lock;

import java.util.Random;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class CountDownLatchDemo implements Runnable {

    static final CountDownLatch end = new CountDownLatch(10);// 创建倒计时器，表示需要等待10个线程，等待在CountDownLatch上的线程才能继续执行
    static final CountDownLatchDemo DEMO = new CountDownLatchDemo();

    public void run() {
        try {
            Thread.sleep(new Random().nextInt(10) * 1000);
            System.out.println(Thread.currentThread().getName() + "----check complete");
            end.countDown();// 通知倒计时器一个线程完事儿,倒计时器减1
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws InterruptedException {
        // 使用倒计时器来模仿火箭发射
        ExecutorService exec = Executors.newFixedThreadPool(10);// 创建10个线程的线程池
        for (int i = 0; i < 10; i++) {
            exec.submit(DEMO);
        }
        end.await();// 倒计时器需要等待10个线程的任务全部完成后，主线程才能继续执行
        System.out.println("火箭发射");
        exec.shutdown();// 关闭线程池
    }

}