JAVA中的CountDownLatch、CyclicBarrier、Semaphore的简单测试

因公司需要做一个对于CountDownLatch的分享，特写了此blog。

具体细节可以参见：小结java自带的跟锁相关的一些类

在做这个分享的过程中发现了Main和junit的运行的区别，在另外一个Blog细说。

详见：http://www.cnblogs.com/yangzhilong/p/6840791.html

 package com.yzl.dubbo;

 import java.util.Random;
 import java.util.concurrent.BrokenBarrierException;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.CyclicBarrier;
 import java.util.concurrent.Semaphore;

 /**
  * 测试CountDownLatch、CyclicBarrier、Semaphore
  * 这里的测试请在Main方法中进行测试，在junit会出现问题，原因是：junit是Daemon线程
  *
  * @author yangzhilong
  *
  */
 public class MyTest {

     public static void main(String[] args) {
         MyTest myTest = new MyTest();
         myTest.testCountDownLatch();
 //        myTest.testCyclicBarrier1();
 //        myTest.testCyclicBarrier2();
 //        myTest.testSemaphore();
     }

     /**
      * 测试CountDownLatch
      *
      */
     @org.junit.Test
     public void testCountDownLatch(){
         CountDownLatch latch = new CountDownLatch(5);

         Thread[] threads = new Thread[5];
         Thread thread = null;

         System.out.println("begin.....................，" + System.currentTimeMillis());
         for (int i = 0; i < 5; i++) {
             final int index = i;
             thread = new Thread(()->{

                 System.out.println("Thread-" + index + ",准备执行!!!，" + System.currentTimeMillis());
                 //计数器减一
                 latch.countDown();
                 try {
                     //等待计数器变成0
                     latch.await();
                 } catch (InterruptedException e) {
                     e.printStackTrace();
                 }
                 System.out.println("Thread-" + index + ",开始执行!!!，" + System.currentTimeMillis());

                 try {
                     Thread.sleep(new Random().nextInt(500));
                 } catch (InterruptedException e1) {
                     e1.printStackTrace();
                 } finally {
                     System.out.println("finally index：" + index);
                 }
                 System.out.println("Thread-" + index + ",执行完成!!!，" + System.currentTimeMillis());

             });
             threads[i] = thread;
         }
         for (Thread t : threads) {
             t.setDaemon(false);
             t.start();
         }
         System.out.println("end..............，" + System.currentTimeMillis());
     }

     /**
      * 测试CyclicBarrier-1
      */
     @org.junit.Test
     public void testCyclicBarrier1(){
         CyclicBarrier cyclicBarrier = new CyclicBarrier(6);

         System.out.println("begin.....................，" + System.currentTimeMillis());
         for (int i = 0; i < 5; i++) {
             final int index = i;
             new Thread(()->{
                 System.out.println("Thread-" + index + ",准备执行!!!，" + System.currentTimeMillis());
                 try {
                     cyclicBarrier.await();
                 } catch (InterruptedException | BrokenBarrierException e) {
                     e.printStackTrace();
                 }
                 System.out.println("Thread-" + index + ",开始执行!!!，" + System.currentTimeMillis());

                 try {
                     Thread.sleep(new Random().nextInt(500));
                 } catch (InterruptedException e1) {
                     e1.printStackTrace();
                 }
                 System.out.println("Thread-" + index + ",执行完成!!!，" + System.currentTimeMillis());
             }).start();;
         }

         try {
             cyclicBarrier.await();
         } catch (InterruptedException | BrokenBarrierException e) {
             e.printStackTrace();
         }

         System.out.println("end..............，" + System.currentTimeMillis());
     }

     /**
      * 测试CyclicBarrier-2
      * 程序中会重置计数器
      */
     @org.junit.Test
     public void testCyclicBarrier2(){
         CyclicBarrier cyclicBarrier = new CyclicBarrier(6);

         System.out.println("begin.....................，" + System.currentTimeMillis());
         for (int i = 0; i < 5; i++) {
             final int index = i;
             new Thread(()->{
                 System.out.println("Thread-" + index + ",准备执行!!!，" + System.currentTimeMillis());
                 try {
                     cyclicBarrier.await();
                 } catch (InterruptedException | BrokenBarrierException e) {
                     e.printStackTrace();
                 }
                 System.out.println("Thread-" + index + ",开始执行!!!，" + System.currentTimeMillis());

                 try {
                     Thread.sleep(new Random().nextInt(500));
                 } catch (InterruptedException e1) {
                     e1.printStackTrace();
                 }

                 System.out.println("Thread-" + index + ",执行完成!!!，" + System.currentTimeMillis());
             }).start();;
         }

         try {
             cyclicBarrier.await();
         } catch (InterruptedException | BrokenBarrierException e) {
             e.printStackTrace();
         }

         System.out.println("end..............，" + System.currentTimeMillis());

         //重置计数器
         cyclicBarrier.reset();

         try {
             cyclicBarrier.await();
         } catch (InterruptedException | BrokenBarrierException e) {
             e.printStackTrace();
         }
         System.out.println("我永远都不能被执行到");
     }

     /**
      * 测试Semaphore
      */
     @org.junit.Test
     public void testSemaphore(){
         Semaphore semaphore = new Semaphore(1);

         System.out.println("begin.....................");
         for (int i = 0; i < 5; i++) {
             final int index = i;
             new Thread(()->{
                 System.out.println("Thread-" + index + ",准备执行!!!，" + System.currentTimeMillis());
                 try {
                     semaphore.acquire();
                 } catch (InterruptedException e) {
                     e.printStackTrace();
                 }
                 System.out.println("Thread-" + index + ",开始执行!!!");

                 try {
                     Thread.sleep(new Random().nextInt(500));
                 } catch (InterruptedException e1) {
                     e1.printStackTrace();
                 }

                 System.out.println("Thread-" + index + ",执行完成!!!");
                 semaphore.release();
             }).start();
         }
         System.out.println("end..............");
         try {
             Thread.sleep(100000L);
         } catch (InterruptedException e) {
             e.printStackTrace();
         }
     }
 }

运行结果：

begin.....................，1494483205995
end..............，1494483206092
Thread-0,准备执行!!!，1494483206094
Thread-2,准备执行!!!，1494483206094
Thread-3,准备执行!!!，1494483206094
Thread-4,准备执行!!!，1494483206094
Thread-1,准备执行!!!，1494483206094
Thread-1,开始执行!!!，1494483206094
Thread-2,开始执行!!!，1494483206095
Thread-0,开始执行!!!，1494483206095
Thread-3,开始执行!!!，1494483206095
Thread-4,开始执行!!!，1494483206095
finally index：4
Thread-4,执行完成!!!，1494483206260
finally index：1
Thread-1,执行完成!!!，1494483206390
finally index：0
Thread-0,执行完成!!!，1494483206483
finally index：3
Thread-3,执行完成!!!，1494483206548
finally index：2
Thread-2,执行完成!!!，1494483206567

begin.....................，1494483641348
Thread-0,准备执行!!!，1494483641454
Thread-1,准备执行!!!，1494483641454
Thread-2,准备执行!!!，1494483641454
Thread-3,准备执行!!!，1494483641455
Thread-4,准备执行!!!，1494483641455
end..............，1494483641455
Thread-1,开始执行!!!，1494483641456
Thread-0,开始执行!!!，1494483641456
Thread-2,开始执行!!!，1494483641456
Thread-3,开始执行!!!，1494483641456
Thread-4,开始执行!!!，1494483641456
Thread-3,执行完成!!!，1494483641502
Thread-0,执行完成!!!，1494483641509
Thread-4,执行完成!!!，1494483641545
Thread-1,执行完成!!!，1494483641564
Thread-2,执行完成!!!，1494483641692

begin.....................，1494483670144
Thread-0,准备执行!!!，1494483670268
Thread-1,准备执行!!!，1494483670268
Thread-2,准备执行!!!，1494483670268
Thread-3,准备执行!!!，1494483670268
Thread-4,准备执行!!!，1494483670268
Thread-4,开始执行!!!，1494483670269
Thread-3,开始执行!!!，1494483670269
Thread-2,开始执行!!!，1494483670269
Thread-0,开始执行!!!，1494483670269
Thread-1,开始执行!!!，1494483670269
end..............，1494483670269
Thread-3,执行完成!!!，1494483670399
Thread-2,执行完成!!!，1494483670404
Thread-1,执行完成!!!，1494483670486
Thread-0,执行完成!!!，1494483670536
Thread-4,执行完成!!!，1494483670553

begin.....................
Thread-0,准备执行!!!，1494483690182
end..............
Thread-0,开始执行!!!
Thread-1,准备执行!!!，1494483690183
Thread-2,准备执行!!!，1494483690183
Thread-3,准备执行!!!，1494483690184
Thread-4,准备执行!!!，1494483690184
Thread-0,执行完成!!!
Thread-1,开始执行!!!
Thread-1,执行完成!!!
Thread-2,开始执行!!!
Thread-2,执行完成!!!
Thread-3,开始执行!!!
Thread-3,执行完成!!!
Thread-4,开始执行!!!
Thread-4,执行完成!!!