使用CountDownLatch計數器模擬賽跑比賽

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

/**
 *模擬賽跑比賽
 *要求:
 *1、裁判等待隊員準備;
 *2、裁判發起起跑通知;
 *3、裁判等待各隊員到達終點
 */
public class ThreadTest2 {

    public static void main
 
(String[] args) {

        //出發倒計時
        CountDownLatch cdl1=new CountDownLatch(1),//裁判起跑通知
                       cdl2=new CountDownLatch(3),//準備完畢通知裁判
                       cdl3=new CountDownLatch(3);//裁判接收到結束通知


        ExecutorService threadPool=Executors.newCachedThreadPool();

        for(int i=0;i<3
 
;i++){
            threadPool.execute(new Runnable(){

                @Override
                public void run() {
                    // TODO Auto-generated method stub
                    System.out.println("隊員"+Thread.currentThread().getName()+"準備完畢");
                    cdl2.countDown();
                    try
 
 {
                        cdl1.await();
                        System.out.println("隊員"+Thread.currentThread().getName()+"出發");

                        Thread.sleep(new Random().nextInt(5)*1000);

                        System.out.println("隊員"+Thread.currentThread().getName()+"到達終點");
                        cdl3.countDown();

                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }




                }

            });
        }

        System.out.println("裁判等待所有隊員準備完畢");
        try {
            cdl2.await();

            Thread.sleep(new Random().nextInt(3)*1000);

            System.out.println("開始");
            cdl1.countDown();

            System.out.println("裁判等待所有隊員結束");
            cdl3.await();

            System.out.println("GOOD GAME!");

            threadPool.shutdown();


        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


    }

}