延迟队列

与时间相关场景的应用，经常用于延后多少时间执行什么任务。

java 自带延迟队列

class Solution {public static void main(String[] args) throws InterruptedException {DelayQueue<DelayMealTask> queue = new DelayQueue<>();DelayMealTask task = new DelayMealTask(System.nanoTime() + ThreadLocalRandom.current().nextLong(100000000L, 300000000L));queue.add(task);StopWatch stopWatch = new StopWatch();stopWatch.start();System.out.println("begin to take task");DelayMealTask take = queue.take();System.out.println("get task complete id :" + take.getTaskId());stopWatch.stop();System.out.println("cost time : " + stopWatch.getTotalTimeMillis());}
}
// output ~//begin to take task
//get task complete id :1
//cost time : 110

redis 延迟队列