Java之CountDownLatch使用

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CountDownLatch，一个同步辅助类，在完成一组正在其他线程中执行的操作之前，它允许一个或多个线程一直等待。

主要方法

 public CountDownLatch(int count);

 public void countDown();

 public void await() throws InterruptedException  

构造方法参数指定了计数的次数

countDown方法，当前线程调用此方法，则计数减一

awaint方法，调用此方法会一直阻塞当前线程，直到计时器的值为0

例子

Java代码  

1. public class CountDownLatchDemo {  
2.     final static SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
3.     public static void main(String[] args) throws InterruptedException {  
4.         CountDownLatch latch=new CountDownLatch(2);//两个工人的协作  
5.         Worker worker1=new Worker("zhang san", 5000, latch);  
6.         Worker worker2=new Worker("li si", 8000, latch);  
7.         worker1.start();//  
8.         worker2.start();//  
9.         latch.await();//等待所有工人完成工作  
10.         System.out.println("all work done at "+sdf.format(new Date()));  
11.     }  
12.       
13.       
14.     static class Worker extends Thread{  
15.         String workerName;   
16.         int workTime;  
17.         CountDownLatch latch;  
18.         public Worker(String workerName ,int workTime ,CountDownLatch latch){  
19.              this.workerName=workerName;  
20.              this.workTime=workTime;  
21.              this.latch=latch;  
22.         }  
23.         public void run(){  
24.             System.out.println("Worker "+workerName+" do work begin at "+sdf.format(new Date()));  
25.             doWork();//工作了  
26.             System.out.println("Worker "+workerName+" do work complete at "+sdf.format(new Date()));  
27.             latch.countDown();//工人完成工作，计数器减一  
28.   
29.         }  
30.           
31.         private void doWork(){  
32.             try {  
33.                 Thread.sleep(workTime);  
34.             } catch (InterruptedException e) {  
35.                 e.printStackTrace();  
36.             }  
37.         }  
38.     }  
39.       
40.        
41. }  

public class CountDownLatchDemo {
	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();
			}
    	}
    }
    
     
}

输出：

Worker zhang san do work begin at 2011-04-14 11:05:11 Worker li si do work begin at 2011-04-14 11:05:11 Worker zhang san do work complete at 2011-04-14 11:05:16 Worker li si do work complete at 2011-04-14 11:05:19 all work done at 2011-04-14 11:05:19

Java之CountDownLatch使用

标签：操作   技术   display   star   htm   none   方法   style   构造   

原文地址：http://www.cnblogs.com/xuxiuxiu/p/7797853.html