怎么样在jQuery progressbar中通过Ajax请求实现后台进度实时功能？
本文主要演示Jquery progressbar的进度条功能。js通过ajax请求向后台实时获取当前的进度值。后台将进度值存储在cookie中，每次请求后，将进度条的值增2个。以此演示进度条的实时显示功能。
前台index.jsp
jsp代码如下
<%@ 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"> -->
<!DOCTYPE html>
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<link rel="stylesheet" type="text/css" href="js/themes/default/easyui.css">
<link rel="stylesheet" type="text/css" href="js/themes/icon.css">
<link rel="stylesheet" type="text/css" href="js/demo/demo.css">
<script type="text/javascript" src="js/jquery.min.js"></script>
<script type="text/javascript" src="js/jquery.easyui.min.js"></script>
<script type='text/javascript'>
var timerId;
$(function(){
//每隔0.5秒自动调用方法，实现进度条的实时更新
timerId=window.setInterval(getForm,500);
});
function getForm(){
//使用JQuery从后台获取JSON格式的数据
$.ajax({
type:"post",//请求方式
url:"getProgressValueByJson",//发送请求地址
timeout:30000,//超时时间：30秒
dataType:"json",//设置返回数据的格式
//请求成功后的回调函数 data为json格式
success:function(data){
if(data.progressValue>=100){
window.clearInterval(timerId);
}
$('#p').progressbar('setValue',data.progressValue);
},
//请求出错的处理
error:function(){
window.clearInterval(timerId);
alert("请求出错");
}
});
}
</script>
</head>
<body>
<div style="margin:100px 0;"></div>
<div id="p" class="easyui-progressbar" style="width: 400px;"></div>
</body>
</html>
struts.xml文件的配置
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <constant name="struts.devMode" value="true" /> <package name="front" extends="struts-default" namespace="/"> <action name="getProgressValueByJson" class="edu.njupt.zhb.test.TestAction" method="getProgressValueByJson"> <result name="success"></result> </action> <action name="TestAction" class="edu.njupt.zhb.test.TestAction"> <result type="httpheader"></result> </action> </package> </struts>
后台的java代码（）
package edu.njupt.zhb.test;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
/*
*@author: ZhengHaibo
*web: http://blog.csdn.net/nuptboyzhb
*mail: zhb931706659@126.com
*Sep 13, 2013 Nanjing,njupt,China
*/
public class TestAction extends ActionSupport {
/**
*
*/
private static final long serialVersionUID = -8697049781798812644L;
/**
* 通过Ajax获取json格式的ProgressBar值
* Type：Action
*/
public void getProgressValueByJson(){
String progressValueString = getCookie(getRequest(),"progressValue");
int progressValue = Integer.parseInt(progressValueString);
if(progressValue>100){
progressValue = 0;
}
System.out.println(" getCookie:---progressValue="+progressValue);
writeJsonString("{\"progressValue\":\"" + progressValue + "\"}");
progressValue += 2;
setCookie(getResponse(),"progressValue",progressValue+"",365*24*60*60);
}
/**
* Get HttpServletRequest Object
* @return HttpServletRequest
*/
public HttpServletRequest getRequest(){
return ServletActionContext.getRequest();
}
/**
* Get HttpServletResponse Object
* @return HttpServletResponse
*/
protected HttpServletResponse getResponse() {
return ServletActionContext.getResponse();
}
/**
* Get PrintWriter Object
* @return PrintWriter
* @throws IOException
*/
protected PrintWriter getWriter() throws IOException {
return this.getResponse().getWriter();
}
/**
* 写Json格式字符串
* @param json
*/
protected void writeJsonString(String json) {
try {
getResponse().setContentType("text/html;charset=UTF-8");
this.getWriter().write(json);
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 获取cookie
* @param request
* @param name
* @return String
*/
public static String getCookie(HttpServletRequest request, String name) {
String value = null;
try {
for (Cookie c : request.getCookies()) {
if (c.getName().equals(name)) {
value = c.getValue();
}
}
} catch (Exception e) {
e.printStackTrace();
}
return value;
}
/**
* 设置cookie
* @param response
* @param name
* @param value
* @param period
*/
public static void setCookie(HttpServletResponse response, String name, String value, int period) {
try {
Cookie div = new Cookie(name, value);
div.setMaxAge(period);
response.addCookie(div);
} catch (Exception e) {
e.printStackTrace();
}
}
}
运行
将项目部署到Tomcat上之后，在浏览器中输入URL，则可以看到进度条逐渐更新
源码下载：http://xiazai.jb51.net/201610/yuanma/jqueryProgressbar(jb51.net).rar
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