package ch03;

 import java.util.Random;

 import java.util.concurrent.CountDownLatch;

 import java.util.concurrent.ExecutorService;

 import java.util.concurrent.Executors;

 public class CountDownLatchTest {

     public static void main(String[] args) {

         ExecutorService threadPool = Executors.newCachedThreadPool();

         //初始值设置为2

         final CountDownLatch latch = new CountDownLatch(2);

         for(int i=0; i<2; i++){

             Runnable runnable = new Runnable() {

                 @Override

                 public void run() {

                     try {

                         Thread.sleep(new Random().nextInt(6000));

                         System.out.println("子线程执行。。。");

                         //计数器自减

                         latch.countDown();

                     } catch (Exception e) {

                         e.printStackTrace();

                     }

                 }

             };

             threadPool.execute(runnable);

         }

         try {

             //等待计数器自减到0，然后再往下执行。

             latch.await();

         } catch (InterruptedException e) {

             e.printStackTrace();

         }

         System.out.println("主线程....");

     }

 }