DelayQueue使用

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使用延迟队列的元素必须实现Delayed接口

public class Task implements Delayed {    /**     * 到期时间，单位是秒     */    private final long timeOut;    /**     * 问题对象     */    private final Question question;    /**     * 产生序列号     */    private static final AtomicLong atomic = new AtomicLong(0);    /**     * 序列号     */    private final long sequenceNum;    public Task(long timeout, Question question) {        this.timeOut = System.nanoTime() + TimeUnit.NANOSECONDS.convert(timeout, TimeUnit.SECONDS);        this.question = question;        this.sequenceNum = atomic.getAndIncrement();    }    /**     * 返回与此对象相关的剩余延迟时间，以给定的时间单位表示     */    @Override    public long getDelay(TimeUnit unit) {        return unit.convert(this.timeOut - System.nanoTime(), TimeUnit.NANOSECONDS);    }    /**     * 元素的先后顺序     * @param other     * @return     */    @Override    public int compareTo(Delayed other) {        if (other == this) // compare zero ONLY if same object            return 0;        if (other instanceof Task) {            Task x = (Task) other;            long diff = timeOut - x.timeOut;            if (diff < 0)                return -1;            else if (diff > 0)                return 1;            else if (sequenceNum < x.sequenceNum)                return -1;            else                return 1;        }        long d = (getDelay(TimeUnit.NANOSECONDS) - other.getDelay(TimeUnit.NANOSECONDS));        return (d == 0) ? 0 : ((d < 0) ? -1 : 1);    }    public Question getQuestion() {        return question;    }}

任务对象

public class Question {    private boolean resloved;    private String number;    public Question(boolean resloved, String number) {        this.resloved = resloved;        this.number = number;    }    public void setResloved(boolean resloved) {        this.resloved = resloved;    }    @Override    public String toString() {        return "Question{" +                "resloved=" + resloved +                ", number='" + number + '\'' +                '}';    }}

执行任务

import java.util.concurrent.DelayQueue;/** * Created by Administrator on 2017/5/26. */public class Job {    private Thread daemonThread;    private DelayQueue<Task> delayQueue = new DelayQueue<Task>();    public Job(){        Runnable daemonTask = new DaemonThread();        daemonThread = new Thread(daemonTask);        daemonThread.setName("Cache Daemon");        daemonThread.start();    }    //执行线程    class DaemonThread implements Runnable{        @Override        public void run() {            execute();        }    }    /**     * 添加任务，     * time 延迟时间,时间是秒     * q 问题     * 用户为问题设置延迟时间     */    public void put(long time,Question q){        //创建一个任务        Task k = new Task(time,q);        //将任务放在延迟的队列中        delayQueue.put(k);    }    public void execute(){        System.out.println("start");        while(true) {            try {                //从延迟队列中取值,如果没有对象过期则队列一直等待，                Task t1 = delayQueue.poll();                if (t1 != null) {                    //修改问题的状态                    Question q = t1.getQuestion();                    System.out.println("修改前"+q);                    q.setResloved(true);                    System.out.println("修改后"+q);                }            } catch (Exception e) {                e.printStackTrace();                break;            }        }    }    public static void main(String[] args) {        Job job = new Job();        Question question1 = new Question(false,"00888");        job.put(5,question1);        for (int i = 0; i < 10; i++){            Question question = new Question(false,"00"+i);            job.put(5,question);        }    }}

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