jee中实现定时执行

编写一个监听器，并在web.xml中注册.
package com.backup.listener;
import java.util.Timer;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
public class AppListener implements ServletContextListener{
    private Timer timer=null;   
    public void contextDestroyed(ServletContextEvent event) {
        if(timer!=null){
            timer.cancel();
        }
        event.getServletContext().log("定时器销毁");
    }
    public void contextInitialized(ServletContextEvent event) {
        timer   =   new   java.util.Timer(true);     
        event.getServletContext().log("定时器已启动");
        timer.schedule(new MyTask(event.getServletContext()),0,1000);     
        event.getServletContext().log("已经添加任务调度表");
    }
}

TimerTask类:
package com.backup.listener;
import java.util.Calendar;
import java.util.Date;
import java.util.TimerTask;
import javax.servlet.ServletContext;
public class MyTask extends TimerTask {
    private static final int C_SCHEDULE_HOUR = 0;
    private static boolean isRunning = false;
    private ServletContext context = null;
    public static boolean isSunday=false;
    public MyTask(ServletContext context) {
        this.context = context;
    }
    public   void   run(){
       context.log("看一看是不是不断的执行");
           Calendar   cal   =   Calendar.getInstance();
           if(!isRunning){    
             System.err.println("开始执行任务");
               if(C_SCHEDULE_HOUR   ==   cal.get(Calendar.HOUR_OF_DAY))   {
                       isRunning   =   true;                                    
                       context.log("开始执行指定任务");    
                          
                       //TODO   添加自定义的详细任务，以下只是示例    
                       int   i   =   0;    
                       while   (i++   <   10)   {    
                               context.log("已完成任务的"   +   i   +   "/"   +   10);    
                       }    
                       isRunning  =  false;    
                       context.log("指定任务执行结束");
                   }
           }else{    
                context.log("上一次任务执行还未结束");    
           }    
     }    
}

从网上找的也不错:

web.xml

<servlet >
     <servlet-name >taskservlet</servlet-name >
    <servlet-class >common.timer.ConvergeDataServlet</servlet-class >
    <init-param >
     <param-name >startTask</param-name >
     <param-value >true</param-value >
    </init-param >
    <init-param >
     <param-name >intervalTime</param-name >
     <param-value >240</param-value >
    </init-param >
    <load-on-startup >300</load-on-startup >
</servlet >

 

ConvergeDataServlet.java

package common.timer;

import java.io.IOException;
import java.util.Timer;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ConvergeDataServlet extends HttpServlet
{
private static final long serialVersionUID = 1L;

private Timer timer1 = null;

private Task task1;

/**  
* Constructor of the object.  
*/
public ConvergeDataServlet() {
   super();
}

/**  
* Destruction of the servlet.
*/
public void destroy() {
   super.destroy();
   if (timer1 != null) {
    timer1.cancel();
   }
}

public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {

}

public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
   doGet(request, response);
}

// init方法启动定时器   
public void init() throws ServletException {

   ServletContext context = getServletContext();

   // (true为用定时间刷新缓存)   
   String startTask = getInitParameter("startTask");

   // 定时刷新时间(分钟)   
   Long delay = Long.parseLong(getInitParameter("intervalTime")) * 60 * 1000;
   // 启动定时器   
   if (startTask.equals("true")) {
    timer1 = new Timer(true);
    task1 = new Task(context);
    timer1.schedule(task1, delay, delay);
   }
}

}

Task.java

package common.timer;

import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.Date;
import java.util.TimerTask;
import javax.servlet.ServletContext;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import tobacco.dayreport.DayreportDAO;
import tobacco.template.service.TobaccoDAOFactory;

public class Task extends TimerTask {

private Logger logger = LogManager.getLogger(Task.class);
private ServletContext context;
private static boolean isRunning = true;

public Task(ServletContext context) {
   this.context = context;
}

public Task() {
}

@Override
public void run() {
   Date d = new Date();
   if (isRunning) {
   }
  
   DayreportDAO dao = (DayreportDAO) TobaccoDAOFactory.getDAO("Dayreport");
   try {
    Timestamp t = new Timestamp(d.getTime());
    dao.dayReports(t);
    logger.debug("=========== 汇总被执行 ==========" + d.toString());
   
   } catch (SQLException ex) {
    ex.printStackTrace();
   }

}

}

 

 

------------------------------------------------------

Java定时任务的实现

本例依据Java自身提供的接口实现，通过监听器（Listener）和定时器（Timer）定时执行某个任务（Task）。
专业的开源工具可参考Quartz：http://www.opensymphony.com/quartz/

MyListener：

import java.util.Timer;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class MyListener implements ServletContextListener {
  
  private Timer timer = null;

  public void contextInitialized(ServletContextEvent event) {
     timer = new Timer(true);
    //设置任务计划，启动和间隔时间
     timer.schedule(new MyTask(), 0, 86400000);
   }

  public void contextDestroyed(ServletContextEvent event) {
     timer.cancel();
   }
  
}

MyTask：

import java.util.TimerTask;

public class MyTask extends TimerTask {

  public void run() {
    // System.out.println("call at " + (new Date()));
    // TODO 此处添加具体任务代码
   }

}

web.xml配置：

<listener>
<listener-class>com.fastunit.samples.listener.MyListener</listener-class>
</listener>

 

 

来自：http://love-love-l.blog.163.com/blog/static/2107830420089151561835/