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多线程定时器 Timer TimerTask

定时器是一种特殊的多线程，使用Timer来安排一次或者重复执行某个任务

 1 package org.zln.thread;
 2 
 3 import java.util.Date;
 4 import java.util.Timer;
 5 import java.util.TimerTask;
 6 
 7 /**
 8  * Created by coolkid on 2015/6/21 0021.
 9  */
10 public class TestTimerTask extends TimerTask {
11     @Override
12     public void run() {
13         System.out.println(new Date());
14     }
15 
16     public static void main(String[] args) {
17         Timer timer = new Timer();
18         TestTimerTask testTimerTask = new TestTimerTask();
19         timer.schedule(testTimerTask,1000,1000);
20 
21     }
22 }

E:GitHub oolsJavaEEDevelopLesson1_JavaSe_Demo1srcorgzln hreadTestTimerTask.java

Timer是一个定时容器，TimerTask子类是具体任务实现类

小练习：

　　间隔一分钟扫描某个目录下是否存在指定文件

 1 package org.zln.thread;
 2 
 3 import java.io.File;
 4 import java.util.Date;
 5 import java.util.Timer;
 6 import java.util.TimerTask;
 7 
 8 /**
 9  * Created by coolkid on 2015/6/21 0021.
10  */
11 public class TestTimerTask extends TimerTask {
12 
13     private String path;
14     private boolean flag = true;
15 
16     public TestTimerTask(String path) {
17         this.path = path;
18     }
19 
20     @Override
21     public void run() {
22         File file = new File(path);
23         if (flag&&!file.isDirectory()&&file.exists()){
24             System.out.println(new Date()+"已检测到文件");
25             flag = false;
26         }
27         if (!flag){
28             System.out.println(new Date()+"已经检测到文件，无需再次检测");
29         }
30         if (flag&&(file.isDirectory()||!file.exists())){
31             System.out.println(new Date()+"未检测到文件");
32         }
33     }
34 
35     public static void main(String[] args) {
36         Timer timer = new Timer();
37         TestTimerTask testTimerTask = new TestTimerTask("E:\GitHub\tools\实用jar程序\创建或删除标识文件\zln.txt");
38         timer.schedule(testTimerTask,1000,60000);
39 
40     }
41 }

E:GitHub oolsJavaEEDevelopLesson1_JavaSe_Demo1srcorgzln hreadTestTimerTask.java

其他常用Timer方法

Modifier and Type	Method and Description
`void`	`cancel()` Terminates this timer, discarding any currently scheduled tasks.
`int`	`purge()` Removes all cancelled tasks from this timer's task queue.
`void`	`schedule(TimerTask task, Date time)` Schedules the specified task for execution at the specified time.
`void`	`schedule(TimerTask task, Date firstTime, long period)` Schedules the specified task for repeated fixed-delay execution, beginning at the specified time.
`void`	`schedule(TimerTask task, long delay)` Schedules the specified task for execution after the specified delay.
`void`	`schedule(TimerTask task, long delay, long period)` Schedules the specified task for repeated fixed-delay execution, beginning after the specified delay.
`void`	`scheduleAtFixedRate(TimerTask task, Date firstTime, long period)` Schedules the specified task for repeated fixed-rate execution, beginning at the specified time.
`void`	`scheduleAtFixedRate(TimerTask task, long delay, long period)` Schedules the specified task for repeated fixed-rate execution, beginning after the specified delay.

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原文地址：https://www.cnblogs.com/sherrykid/p/4592363.html

多线程 定时器 Timer TimerTask

多线程定时器 Timer TimerTask