countdown设计模式

• 使用JDK自带的countdownLatch

public class JDKCountDown {

    private static final Random random = new Random(System.currentTimeMillis());

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

        final CountDownLatch latch = new CountDownLatch(5);
        System.out.println("准备多线程处理任务.");
        //The first phase.

        IntStream.rangeClosed(1, 5).forEach(i ->
                new Thread(() -> {
                    System.out.println(Thread.currentThread().getName() + " is working.");
                    try {
                        Thread.sleep(random.nextInt(1000));
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    latch.countDown();
                }, String.valueOf(i)).start()
        );

        latch.await();
        //The second phase.
        System.out.println("多线程任务全部结束,准备第二阶段任务");
        System.out.println("............");
        System.out.println("FINISH");

    }
}