CountDownLatch 线程工具的使用

最新推荐文章于 2025-04-30 10:23:57 发布

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本文探讨了Java并发编程中的线程池、CountDownLatch等工具的使用，通过实例展示了线程之间的协作与命令流程，包括命令的发布、接收与响应处理。

package test;

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


public class Test2 {

	public static void main(String[] args) {
          ExecutorService service=Executors.newCachedThreadPool();
          final CountDownLatch cdOrder = new CountDownLatch(1);
          final CountDownLatch cdAnswer = new CountDownLatch(3);
          for(int i=0;i<3;i++){
        	  Runnable runnable=new Runnable(){
        		  @Override
        		public void run() {
                   
                 	try {
                 		  System.out.println("线程:"+Thread.currentThread().getName()+"正在准备接受命令");
						  cdOrder.await();
						  System.out.println("线程"+Thread.currentThread().getName()+"已经接受命令");
						  Thread.sleep((long) (Math.random()*10000));
						  System.out.println("线程"+Thread.currentThread().getName()+"回应命令处理结果");
					} catch (InterruptedException e) {
						
					}
                 	
        		}  
        	  };
        	  service.execute(runnable);
          }
          try {
			Thread.sleep((long)(Math.random()*10000));
			System.out.println("线程"+Thread.currentThread().getName()+"即将发布命令");
			cdOrder.countDown();
			System.out.println("线程" + Thread.currentThread().getName() + 
					"已发送命令，正在等待结果");	
			cdAnswer.await();
			System.out.println("线程" + Thread.currentThread().getName() + 
					"已收到所有响应结果");	
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
         service.shutdown();
	}
//运动员 百米赛跑 ，首先大家都在等待 中(三个线程在等待接受命令)，当吹口号 的人，吹起号声（已发送命令）， 完成各自的工作。
}

打印结果

线程:pool-1-thread-1正在准备接受命令
线程:pool-1-thread-3正在准备接受命令
线程:pool-1-thread-2正在准备接受命令
线程main即将发布命令
线程main已发送命令，正在等待结果
线程pool-1-thread-3已经接受命令
线程pool-1-thread-1已经接受命令
线程pool-1-thread-2已经接受命令
线程pool-1-thread-1回应命令处理结果
线程pool-1-thread-2回应命令处理结果
线程pool-1-thread-3回应命令处理结果

package test;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.CountDownLatch;

public class Test3 {
	final static SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    public static void main(String[] args) throws InterruptedException {
    	CountDownLatch latch=new CountDownLatch(2);//两个工人的协作
    	Worker worker1=new Worker("zhang san", 5000, latch);
    	Worker worker2=new Worker("li si", 8000, latch);
    	worker1.start();//
    	worker2.start();//
    	latch.await();//等待所有工人完成工作
        System.out.println("all work done at "+sdf.format(new Date()));
	}
    
    
    static class Worker extends Thread{
    	String workerName; 
    	int workTime;
    	CountDownLatch latch;
    	public Worker(String workerName ,int workTime ,CountDownLatch latch){
    		 this.workerName=workerName;
    		 this.workTime=workTime;
    		 this.latch=latch;
    	}
    	public void run(){
    		System.out.println("Worker "+workerName+" do work begin at "+sdf.format(new Date()));
    		doWork();//工作了
    		System.out.println("Worker "+workerName+" do work complete at "+sdf.format(new Date()));
    		latch.countDown();//工人完成工作，计数器减一

    	}
    	
    	private void doWork(){
    		try {
				Thread.sleep(workTime);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
    	}
    }
    
     
}