以前项目中写过类似的定时器,今天复习1下,自己建了个工程.
实现原理:创建servlet,应用服务器自动加载此servlet,在web.xml设置定时器的各个参数
开发工具:myeclipse6.0
应用服务器:tomcat6.0
1、创建web工程TestTimer
2、创建servlet=>com.billy.servlet.TestServlet.java
package com.billy.servlet;
import java.io.IOException;
import java.util.Calendar;
import java.util.Date;
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;
import com.billy.Task;
public class TestServlet extends HttpServlet {
private Timer timer1 = null;
private Task task1;
/**
* Constructor of the object.
*/
public TestServlet() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
if(timer1!=null){
timer1.cancel();
}
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println("doGet");
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println("doPost");
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
System.out.println("init");
ServletContext context = getServletContext();
// 定时器开关
String startTask = getInitParameter("startTask");
System.out.println(startTask);
// 开始运行时间
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY,Integer.parseInt(getInitParameter("startTime")));
Date time = calendar.getTime();
// 缓冲时间(分钟)
Long intervalTime = Long.parseLong(getInitParameter("intervalTime"));
System.out.println(intervalTime);
// 启动定时器
if(startTask.equals("true")){
timer1 = new Timer(true);
task1 = new Task(context);
timer1.schedule(task1, time, intervalTime * 1000 * 60);
}
}
}
//Task为任务类
package com.billy;
import java.util.TimerTask;
import javax.servlet.ServletContext;
public class Task extends TimerTask{
private ServletContext context;
static int i = 1;
private static boolean isRunning = true;
public Task(ServletContext context){
this.context = context;
}
@Override
public void run() {
if(isRunning){
//此处写自己需要循环的业务逻辑
System.out.println("上传文件" + i);
i++;
}
}
}
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="
http://java.sun.com/xml/ns/j2ee
"
xmlns:xsi="
http://www.w3.org/2001/XMLSchema-instance
"
xsi:schemaLocation="
http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd
">
<servlet>
<servlet-name>TestServlet</servlet-name>
<servlet-class>com.billy.servlet.TestServlet</servlet-class>
<init-param>
<!-- // 定时器开关 -->
<param-name>startTask</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<!-- // 开始运行时间 HH-->
<param-name>startTime</param-name>
<param-value>12</param-value>
</init-param>
<init-param>
<!-- // 缓冲时间 MM-->
<param-name>intervalTime</param-name>
<param-value>1</param-value>
</init-param>
<load-on-startup>300</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>TestServlet</servlet-name>
<url-pattern>/wangweiTest</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
目录结构:
