CountDownLatch和CyclicBarrier的用法

CountDownLatch 用法

// 用于多线程的统计 -1
        final CountDownLatch countDownLatch = new CountDownLatch(2);
        countDownLatch.countDown();   // 调用一次就-1 ，可以将对象传到其它线程调用
        System.out.println("countDownLatch = " + countDownLatch);
//        countDownLatch.await();     // countDownLatch 的值不为0的话，会一直等待
        boolean await = countDownLatch.await(1, TimeUnit.SECONDS);// 等待 3秒,如果countDownLatch 不为0返回false
        System.out.println("await = " + await);

 

 // CyclicBarrier 

public static void main(String[] args) throws InterruptedException, BrokenBarrierException, TimeoutException {

    // 三条线程， 必须所有线程都完成了，再往下走
    final CyclicBarrier cyclicBarrier = new CyclicBarrier(3);
    for (int i = 0; i < cyclicBarrier.getParties(); i++) {
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println("aaaa");
                try {
                    //                        Thread.sleep(3000);
                    cyclicBarrier.await();
                } catch (InterruptedException | BrokenBarrierException e) {
                    e.printStackTrace();
                }
            }
        });
        thread.start();
    }
    cyclicBarrier.await(1,TimeUnit.SECONDS);  // 如超过等待时间的话，没有越过，就往下走

    final int parties = cyclicBarrier.getParties();
    System.out.println("parties = " + parties);
}