辅助类 CountDownLatch、CyclicBarrier、Semaphore

CountDownLatch的使用

/*
  减法计数器
*/
public class Test1 {
    public static void main(String[] args) throws InterruptedException {
        CountDownLatch countDownLatch = new CountDownLatch(10);//一共减10次

        for (int i = 1; i < 11; i++) {
            new Thread(()->{
                System.out.println(Thread.currentThread().getName() + " Go Out");
                countDownLatch.countDown();//每次减一
            }, String.valueOf(i)).start();
        }
        countDownLatch.await();//等待计数器归零 再继续向下执行
        System.out.println("Close Door");
    }
}

CyclicBarrier的使用

/*
  加法计数器
*/
public class Test {
    public static void main(String[] args) {
        CyclicBarrier cyclicBarrier = new CyclicBarrier(7, ()->{
            System.out.println("集齐了龙珠");
        });

        for (int i = 1; i < 8; i++) {
            int temp = i;
            new Thread(/*()->{
                System.out.println(Thread.currentThread().getName()+"收集第"+ temp +"颗龙珠");
                try {
                    cyclicBarrier.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } catch (BrokenBarrierException e) {
                    e.printStackTrace();
                }
            }*/
                    new Runnable() {
                        @Override
                        public void run() {
                            System.out.println(Thread.currentThread().getName()+"收集第"+ temp +"颗龙珠");
                            try {
                                cyclicBarrier.await();
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            } catch (BrokenBarrierException e) {
                                e.printStackTrace();
                            }
                        }
                    }, String.valueOf(temp)).start();
        }
    }
}

Semaphore的使用

/*
  线程数量限制
*/
public class Test3 {
    public static void main(String[] args) {
        //线程数量  限流用
        Semaphore semaphore = new Semaphore(3);

        for (int i = 1; i < 7; i++) {
            new Thread(()->{
                try {
                    semaphore.acquire();//抢到车位
                    System.out.println(Thread.currentThread().getName()+"抢到了车位");
                    TimeUnit.SECONDS.sleep(1);
                    System.out.println(Thread.currentThread().getName()+"离开了车位");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }finally {
                    semaphore.release();//离开车位
                }
            }, String.valueOf(i)).start();
        }
    }
}