使用listener做定时任务

package com.listener;

import java.util.Date;
import java.util.TimerTask;

public class MyTask extends TimerTask{
	
	private static boolean isRunning = false;
	public void run() {
		// TODO Auto-generated method stub
		if(!isRunning)
		{
			isRunning = true;
			System.out.println(new Date()+"任务开始");
			for (int i = 0; i <100; i++) 
			{
				System.out.println(new Date()+"任务完成"+i+"/"+100);
				try {
					Thread.sleep(50);//休眠50毫秒进入下一次循环
				} catch (Exception e) {
					// TODO: handle exception
					e.printStackTrace();
				}
			}
			isRunning = false;
			System.out.println(new Date()+"所有任务完成");
		}
		else
		{
			System.out.println(new Date()+"任务退出");
		}
	}

}

 package com.listener;

import java.util.Date;
import java.util.Timer;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class TestListener implements ServletContextListener {
	
	
	private Timer timer = null;
	public void contextDestroyed(ServletContextEvent sce) {
		
		timer.cancel();
		sce.getServletContext().log(new Date()+"计时器销毁");
	}

	public void contextInitialized(ServletContextEvent sce) {
		
		timer = new Timer(true);
		sce.getServletContext().log(new Date()+"计时器已经启动");
		timer.schedule(new MyTask(), 0,60*1000);//间隔一分钟执行下一次定时任务
		sce.getServletContext().log(new Date()+"计时器执行一次");
	}

}