CountDownLatch 示例

public class CountDownLatchTest {
    
    public static void main(String[] args) throws InterruptedException {
        
        //倒数计数器
        final CountDownLatch begin = new CountDownLatch(1);
        
        //倒数计数器
        final CountDownLatch end = new CountDownLatch(10);
        
        //十名枪手
        ExecutorService execu = Executors.newFixedThreadPool(10);
        
        //模拟招募10名枪手到齐后开动大巴，送往“战场”
        for(int i=0;i<10;i++){
            
            final int NO = i+1;
            
            Runnable r = new Runnable() {
                
                @Override
                public void run() {
                    
                    try {
                        
                        //等待招募者下令招募
                        begin.await();
                        
                        Thread.sleep((long) (Math.random()*10000));
                        
                        System.out.println("枪手:"+NO+"到了");
                        
                    } catch (InterruptedException e) {
                        
                        e.printStackTrace();
                        
                    }finally{
                        
                        //每到达一个枪手，计数器减1
                        end.countDown();
                    }
                }
            };
            
            execu.submit(r);
        }
        
        //begin倒数计数器减1为0，则开始下招募令，一声令下
        begin.countDown();
        
        System.out.println("开始招募。。。。");
        
        //等待所有的枪手到达
        end.await();
        
        //所有枪手到达
        System.out.println("所有枪手到达,开动大巴,送往目的地。。。。");
        
        execu.shutdown();
        
    
    }
}