j2ee执行定时任务

第一步:编译两个类文件

 

1.SysListener.java

//---------------------------------------------

package com.initpower.webapp.listener;

 

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import java.io.IOException;
import java.util.Timer;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;

 

public class SysListener extends HttpServlet implements ServletContextListener {

 private static final long serialVersionUID = 1L;

 Timer timer = new Timer();

 public void service(ServletRequest request, ServletResponse response)
   throws ServletException, IOException {
 }

 public void contextInitialized(ServletContextEvent sce) {
  System.out.println("系统定时任务初始化开始....");
  // 调用任务
  // 每10秒执行一次
  timer.schedule(new UserOnlineTimerTask(), 0, 10000);
 }

 public void contextDestroyed(ServletContextEvent sce) {
  System.out.println("系统定时任务初始化结束....");
  timer.cancel();
 }

}

2. UserOnlineTimerTask.java

//---------------------------------------------

package com.initpower.webapp.listener;

import java.util.TimerTask;

import com.initpower.common.tools.DateBean;

 

public class UserOnlineTimerTask extends TimerTask {

 public void run() {
  try {
   System.out.println("["+DateBean.nowTimeStr()+"]"+"正在执行...");
   //Runtime.getRuntime().exec("regedit");
   
  } catch (Exception e) {
   System.out.println("定时任务执行失败!");
   e.printStackTrace();
  }
 }

}

 

第二步:编辑j2ee应用程序的web.xml

在<web-app>节点内加入:

<!-- Timer -->
 <listener>
  <listener-class>com.initpower.webapp.listener.SysListener</listener-class>
 </listener>

第三步:启动tomcat5之类的web容器

 

屏幕上显示:时间+"正在执行..."