线程：CyclicBarrier同步工具类

 1 package ch03;
 2 
 3 import java.util.Random;
 4 import java.util.concurrent.CyclicBarrier;
 5 import java.util.concurrent.ExecutorService;
 6 import java.util.concurrent.Executors;
 7 import java.util.concurrent.TimeUnit;
 8 
 9 public class CyclicBarrierTest {
10 
11     public static void main(String[] args) {
12         final int count = 3;
13         //线程池
14         ExecutorService threadPool = Executors.newFixedThreadPool(count);
15         //实例化CyclicBarrier对象，并指定当到达屏蔽点的时候，
16         //需要执行的 操作，该操作由最后一个到达的线程执行。
17         final CyclicBarrier barrier = new CyclicBarrier(count, new Runnable() {
18             
19             @Override
20             public void run() {
21                 System.out.println("前往下一个地点...");
22             }
23         });
24         System.out.println("参与个数："+barrier.getParties());
25         for(int i=0; i<count; i++){
26             Runnable runnable = new Runnable() {
27                 
28                 @Override
29                 public void run() {
30                     try{
31                         Thread.sleep(new Random().nextInt(5000));
32                         System.out.println(Thread.currentThread().getName()+
33                                 "到达指定地点A,当前已有"+
34                                 (barrier.getNumberWaiting()+1)+"人到达,"+
35                                 (barrier.getNumberWaiting() == (count -1) ? "继续前进...":"等待其他人到来"));
36                         //等待3个线程全部到达，当等待时间超过15s时，将报错
37                         barrier.await(10, TimeUnit.SECONDS);
38                         
39                         Thread.sleep(new Random().nextInt(5000));
40                         System.out.println(Thread.currentThread().getName()+"到达指定地点B,当前已有"+
41                                 (barrier.getNumberWaiting()+1)+"人到达,"+
42                                 (barrier.getNumberWaiting() == (count -1) ? "继续前进...":"等待其他人到来"));
43                         barrier.await();
44                     }catch(Exception e){
45                         e.printStackTrace();
46                     }
47                 }
48             };
49             threadPool.execute(runnable);
50         }
51         threadPool.shutdown();
52     }
53 
54 }