CountDownLatch 的使用

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  

public class
final static SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
public static void main(String[] args) throws
new CountDownLatch(2);//两个工人的协作
new Worker("zhang san", 5000, latch);  
new Worker("li si", 8000, latch);  
//
//
//等待所有工人完成工作
"all work done at "+sdf.format(new
    }  
      
      
static class Worker extends
        String workerName;   
int
        CountDownLatch latch;  
public Worker(String workerName ,int
this.workerName=workerName;  
this.workTime=workTime;  
this.latch=latch;  
        }  
public void
"Worker "+workerName+" do work begin at "+sdf.format(new
//工作了
"Worker "+workerName+" do work complete at "+sdf.format(new
//工人完成工作，计数器减一
  
        }  
          
private void
try
                Thread.sleep(workTime);  
catch
                e.printStackTrace();  
            }  
        }  
    }  
      
       
}