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定时循环执行任务

    博客分类：
  • Java
ServletWebHTMLXML 
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web.xml的配置

<servlet>
        <description>定时发信</description>
        <display-name>定时发信</display-name>
        <servlet-name>TaskMail</servlet-name>
        <servlet-class>com.servlet.web.task.TaskMail</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>1</param-value>
        </init-param>
        <load-on-startup>300</load-on-startup>
    </servlet>

Servlet

package com.servlet.web.task;

import java.io.IOException;
import java.io.PrintWriter;
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 TaskMail extends HttpServlet {

   
     private Timer timer1 = null;  
           
     private Task task1; 
    /**
     * Constructor of the object.
     */
    public TaskMail() {
        super();
    }

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

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

        doPost...
    }

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

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
        out.println("<HTML>");
        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("  <BODY>");
        out.print("    This is ");
        out.print(this.getClass());
        out.println(", using the POST method");
        out.println("  </BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

    /**
     * Initialization of the servlet. <br>
     *
     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
           
                 System.out.println("定时发信启动");  
                 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"));  
                   
                 // 启动定时器  
                 if(startTask.equals("true")){  
                     timer1 = new Timer(true);  
                     task1 = new Task(context);  
                     timer1.schedule(task1, delay * 60 * 1000, delay * 60 * 1000);  
                 }
    }

}

 

要执行的任务

package com.servlet.web.task;

import java.util.TimerTask;

import javax.servlet.ServletContext;

public class Task extends TimerTask{

     private ServletContext context;  
           
         private static boolean isRunning = true;  
           
         public Task(ServletContext context){  
             this.context = context;  
         }  
           
               
         @Override 
         public void run() {  
             if(isRunning){  
                 //context.getContextPath();
                 System.out.println("定时发信执行");
             }  
         }   

}

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