java_Timer_schedule jdk自带定时器

浏览数：21 / 时间：2015年06月08日

定时器经常在项目中用到，定制执行某些操作，比如爬虫就需要定时加载种子等操作，之前一直用spring的定制器
近期做项目发现，jdk有很简单的提供   代码如下


 1 /*   
 2  * Copyright (c) 2014-2024 . All Rights Reserved.   
 3  *   
 4  * This software is the confidential and proprietary information of   
 5  * LoongTao. You shall not disclose such Confidential Information   
 6  * and shall use it only in accordance with the terms of the agreements   
 7  * you entered into with LoongTao.   
 8  *   
 9  */
10 package com.loongtao.dmscrawler.temp;
11 
12 import java.util.Timer;
13 import java.util.TimerTask;
14 
15 /**
16  * @declare:测试定时器 <br>
17  * @author: cphmvp
18  * @version: 1.0
19  * @date: 2014-3-14上午11:21:36
20  */
21 public class TimeTest {
22     public static void main(String[] args) {
23         System.out.println("start");
24         new Timer().schedule(new TestTask(), 0, 1000 * 60 * 60);
25         System.out.println("end");
26 
27     }
28 
29     static class TestTask extends TimerTask {
30         TestTask() {
31             // 空构造器
32         }
33 
34         @Override
35         public void run() {
36             System.out.println(1);
37         }
38 
39     }
40 }

jdk源码参考 很容易看懂的 ，不解释

 1   * @param task   task to be scheduled.
 2      * @param delay  delay in milliseconds before task is to be executed.
 3      * @param period time in milliseconds between successive task executions.
 4      * @throws IllegalArgumentException if <tt>delay</tt> is negative, or
 5      *         <tt>delay + System.currentTimeMillis()</tt> is negative.
 6      * @throws IllegalStateException if task was already scheduled or
 7      *         cancelled, timer was cancelled, or timer thread terminated.
 8      */
 9     public void schedule(TimerTask task, long delay, long period) {
10         if (delay < 0)
11             throw new IllegalArgumentException("Negative delay.");
12         if (period <= 0)
13             throw new IllegalArgumentException("Non-positive period.");
14         sched(task, System.currentTimeMillis()+delay, -period);
15     }