博客

   @Test
    public void Juc() throws InterruptedException {

        System.out.println("马上输出");

        DelayQueue<Delayed> delayeds = new DelayQueue<>();
        new Thread(() -> {
            delayeds.offer(new MyDelayedTask("task1", 3000));
            System.out.println("异步");
            try {
                Delayed take = delayeds.take();
                System.out.println("异步三秒后输出");
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }).start();

        System.out.println("主线程");
        while (true){}

    }


    class MyDelayedTask implements Delayed {

        private String name;
        private long start = System.currentTimeMillis();
        private long time;

        public MyDelayedTask(String name, long time) {
            this.name = name;
            this.time = time;
        }

        @Override
        public long getDelay(TimeUnit unit) {
            return unit.convert((start + time) - System.currentTimeMillis(), TimeUnit.MILLISECONDS);
        }

        @Override
        public int compareTo(Delayed o) {
            MyDelayedTask o1 = (MyDelayedTask) o;
            return (int) (this.getDelay(TimeUnit.MILLISECONDS) - o.getDelay(TimeUnit.MILLISECONDS));
        }
    }

1.延迟任务实现delay接口，重写getDalay与compareTo方法

2.DelayQueue创建延迟队列，创建线程，队列添加延迟任务，当队列内任务没有take的时候线程会堵塞