Java工作笔记-使用jquery.timer.js实现数据自动刷新

程序运行截图如下：

程序结构如下：

源码如下：

HelloServlet.java

package my;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HelloServlet extends HttpServlet {

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

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * 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 {

		int n = new UserStat().count();
		String replyText = String.valueOf(n);
		
		response.setContentType("text/plain");
		response.setCharacterEncoding("UTF-8");
		PrintWriter out = response.getWriter();
		out.write(replyText);
		out.close();
	}

	/**
	 * 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 {

		response.setContentType("text/plain");
		response.setCharacterEncoding("UTF-8");
		
		PrintWriter out = response.getWriter();
		out.write("Not Supported");
		out.close();
	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occurs
	 */
	public void init() throws ServletException {
		// Put your code here
	}
}

UserStat.java

package my;

public class UserStat {

	public int count(){
		
		return (int)(Math.random() * 1000);
	}
}

timer.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'new.jsp' starting page</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

	<link rel="stylesheet" href="bootstrap/css/bootstrap.min.css">
	<script src="jquery/jquery.js"></script>
	<script src="bootstrap/js/bootstrap.min.js"></script>
	<script src="jquery/jquery.timer.js"></script>
  </head>
  
	<script >
	
	function trace( msg ){	
	
		try{ 
			console.log(msg); 
		} 
		catch(err){ }
	}
	
	function onQuery()
	{
		jQuery.ajax({			 
			method: "GET",			 
			url: "servlet/HelloServlet",
			success: function(data, textStatus, jqXHR)
			{
				$("#userCount").html(data);
			},
			error: function( jqXHR, textStatus, errorThrown){
				trace( "error: " + errorThrown );	
			}
		});
		
	}
	
	// 页面加载后的初始化工作
	$(document).ready( function(){
		 
		 var timerId = $.timer(1000, onQuery, false);
	});
		
	</script>
  
  <body>
  	<div class="container">
  		<p> 当前共 <span id="userCount"> 0 </span> 人在线 </p>
  	</div>
  </body>
</html>

Java工作笔记-使用jquery.timer.js实现数据自动刷新

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