countdownlatch+cyclicbarrier+semphore

countdown

class q{
    public static void main(String[] args) throws InterruptedException {
        CountDownLatch countDownLatch = new CountDownLatch(5);
        for (int i = 0; i < 5; i++) {
            //开启线程
            new Thread(()->{
                System.out.println(Thread.currentThread().getName()+"就位");
                countDownLatch.countDown();
                System.out.println(Thread.currentThread().getName()+"溜了");
            }).start();
        }
        countDownLatch.await();
        System.out.println("开团");
    }
}

在countdown只是传递信号，没有约束力

cyclicbarrier

class W{
    public static void main(String[] args) throws InterruptedException, BrokenBarrierException {
        //自带了runnable
        CyclicBarrier cyclicBarrier = new CyclicBarrier(5,
                ()-> System.out.println("666开团"));
        for (int i = 0; i < 5; i++) {
            //开启线程
            new Thread(()->{
                System.out.println(Thread.currentThread().getName()+"就位");
                try {
                    cyclicBarrier.await();
                    System.out.println(Thread.currentThread().getName()+"溜了");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } catch (BrokenBarrierException e) {
                    e.printStackTrace();
                }
            }).start();
        }
        System.out.println("开团");
    }
}

这个是有约束了，await就等到集齐，才可以往下走

sempaphore

class cc{
    public static void main(String[] args) {
        Semaphore semaphore = new Semaphore(3);
        for (int i = 0; i < 6; i++) {
            new Thread(()->{
                try {
                    semaphore.acquire();
                    System.out.println(Thread.currentThread().getName()+"抢到女人了");
                    Thread.sleep(11);
                    System.out.println("离开");
                    semaphore.release();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                ;
            }).start();
        }
    }
}

很方便，适用于多个共享资源