Ajax制作Web进度条
1 <%@ page language="java" pageEncoding="UTF-8"%> 2 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 3 <html> 4 <head> 5 <script type="text/javascript" language="javaScript"> 6 var bgcolor = '#7FFF00'; //全局变量，用于设置进度条的背景色 7 var number; //全局变量，用于记录当前span序号 8 var clear = " "; //全局变量，记录清空时的内容 9 var xmlHttp = false; //全局变量，用于记录XMLHttpRequest对象 10 function createXMLHttpRequest() { //创建XMLHttpRequest对象的方法 11 if(window.ActiveXObject) { //Inetrnet Explorer时，创建XMLHttpRequest对象的方法 12 try { 13 xmlHttp = new ActiveXObject("Msxml2.XMLHTTP"); 14 } catch(e) { 15 try { 16 xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); 17 //旧版本的Inetrnet Explorer，创建XMLHttpRequest对象 18 } catch(e) { 19 window.alert("创建XMLHttpRequest对象错误"+e); 20 } 21 } 22 } else if(window.XMLHttpRequest) { //mozilla时，创建XMLHttpRequest对象的方法 23 xmlHttp = new XMLHttpRequest(); 24 } 25 if(!(xmlHttp)) { //未成功创建XMLHttpRequest对象 26 window.alert("创建XMLHttpRequest对象异常！"); 27 } 28 } 29 30 //启动进度条的方法 31 function startRun() { 32 createXMLHttpRequest(); //创建XMLHttpRequest对象 33 clearBar(); //执行请求前先清除进度条 34 xmlHttp.onreadystatechange = callBack; 35 //指定onreadystatechange属性值，用于指定状态正常时的处理函数 36 xmlHttp.open("GET", "/ProgressTest/servlet/ProcessServlet?flag=start", true); 37 xmlHttp.send(null); 38 } 39 40 //开始进行进度条显示的处理函数 41 function callBack() { 42 //window.alert("callBack()"); 43 if(xmlHttp.readyState == 4) { 44 if(xmlHttp.status == 200) { //status状态正常时 45 setTimeout("aginRun()",1000); 46 //每隔1000毫秒（1秒）执行一次“aginRun()”函数 47 } 48 } 49 } 50 51 //清除用于显示进度条的span的内容 52 function clearBar() { 53 for (var i=0;i<10;i++) { //根据span元素的id，分别清楚其显示内容 54 var sp = document.getElementById("sp" + i); 55 sp.innerHTML = clear; //首先清空span元素的内容 56 sp.style.backgroundColor = "white"; //设置span元素的背景色 57 } 58 } 59 //设置用于显示进度条的span元素的显示内容 60 function aginRun() { 61 createXMLHttpRequest(); //创建XMLHttpRequest对象 62 xmlHttp.onreadystatechange = aginCallBack; 63 //指定状态正常时的处理函数为“aginCallBack” 64 document.getElementById("run").disabled=true; //设置按钮不可用 65 xmlHttp.open("GET", "/ProgressTest/servlet/ProcessServlet?flag=run", true); 66 //window.alert(" " + number); 67 xmlHttp.send(null); 68 } 69 70 //进度条执行时的函数 71 function aginCallBack() { 72 if(xmlHttp.readyState==4) { 73 if(xmlHttp.status==200) { 74 var percent = 75 xmlHttp.responseXML.getElementsByTagName("percent")[0].firstChild.data; 76 //记录当前完成比例 77 var index = parseResult(percent); //解析结果集 78 var nextCell = 1; 79 for (var i=0; i<index; i++) { //遍历span元素集合，设置其内容（颜色与文字） 80 var sp = document.getElementById("sp"+i); 81 //根据每个span元素的id获取span对象 82 sp.innerHTML= clear; //清空span元素内容 83 sp.style.backgroundColor = bgcolor; //设置span元素的内容 84 nextCell = i+1; 85 if(nextCell>=index && nextCell<10) { //显示当前处理进度的百分比 86 document.getElementById("sp"+nextCell).innerHTML=percent+"%"; 87 } 88 } 89 if(index<10) { //索引小于10，设置setTimeout方法 90 setTimeout("aginRun()",1000); 91 } else { //索引大于10，设置进度条成功完成的页面效果 92 document.getElementById("result").innerHTML = "OK!"; 93 document.getElementById("run").disabled = false; 94 } 95 } 96 } 97 } 98 99 //解析结果集100 function parseResult(result) {101 if(result.length<1) {102 return 1;103 } else if(result.length==2) {104 return result.substring(0,1);105 } else {106 return 10;107 }108 }109 </script>110 <title>Ajax进度条</title>111 </head>112 <body>113 <table align="center">114 <tr>115 <td>Ajax进度条示例 <input type="button" value="开始" id="run" onclick="startRun();"/></td>116 </tr>117 <tr>118 <td>119 <div id="processBar" style="padding:1px;border:solid black 1px;">120 <span id="sp0"> </span>121 <span id="sp1"> </span>122 <span id="sp2"> </span>123 <span id="sp3"> </span>124 <span id="sp4"> </span>125 <span id="sp5"> </span>126 <span id="sp6"> </span>127 <span id="sp7"> </span>128 <span id="sp8"> </span>129 <span id="sp9"> </span>130 </div>131 </td>132 </tr>133 <tr><td align="center" id="result"></td> </tr>134 </table>135 </body>136 </html>2.ProcessServlet.java
1 public class ProcessServlet extends HttpServlet { 2 3 private static final String CONTENT_TYPE = "text/xml; charset=UTF-8"; 4 //设置返回响应的ContentType 5 private int count = 1;// 全局变量计数器 6 /** 7 *当前Servlet对象构造方法 8 */ 9 public ProcessServlet() {10 super();11 }12 /**13 *当前Servlet销毁时的操作。<br>14 */15 public void destroy() {16 super.destroy();17 }18 /**19 *当前Servlet的doGet方法。<br>20 *21 *当客户端表单的“method”类型为“get”时，调用此方法22 * 23 * @param request客户端请求对象24 * @param response 服务器响应对象25 * @throws ServletException 发生ServeltException时抛出26 * @throws IOException发生IOException时抛出27 */28 public void doGet(HttpServletRequest request, HttpServletResponse response)29 throws ServletException, IOException {30 System.out.println("*********************doGet()**********");31 response.setContentType(CONTENT_TYPE); //设置服务器响应类型32 response.setHeader("Cache-Control","no-cache"); //页面不记录缓存33 String flag = request.getParameter("flag"); //操作类型34 StringBuffer xml= 35 // new StringBuffer("<?xml version="1.0" encoding="UTF-8"?><items>");36 new StringBuffer("<items>");37 //记录返回的xml串38 if("start".equals(flag)) { //第一次创建39 // xml.append("<count>1</count>");40 count = 1;41 } else {42 String proportion = "";43 switch(count) { //根据计数器的值，设置显示当前进度的百分比44 case 1:proportion="10"; break;45 case 2:proportion="20"; break;46 case 3:proportion="30"; break;47 case 4:proportion="40"; break;48 case 5:proportion="50"; break;49 case 6:proportion="60"; break;50 case 7:proportion="70"; break;51 case 8:proportion="80"; break;52 case 9:proportion="90"; break;53 case 10:proportion="100"; break;54 }55 count++;56 xml.append("<percent>").append(proportion).append("</percent>");57 }58 xml.append("</items>");59 PrintWriter out = response.getWriter();60 out.println(xml.toString()); //返回生成的XML串61 out.flush(); //输出流刷新62 out.close(); //关闭输出流63 System.out.println("*********** " + xml.toString());64 }65 66 /**67 * 初始化servlet. <br>68 * @throws ServletException 发生ServletExcpetio异常时抛出69 */70 public void init() throws ServletException {71 }72 }3.web.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <web-app version="2.5" 3 xmlns="http://java.sun.com/xml/ns/javaee" 4 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 5 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 6 http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> 7 <servlet> 8 <servlet-name>ProcessServlet</servlet-name> 9 <servlet-class>wen.ProcessServlet</servlet-class>10 </servlet>11 <servlet-mapping>12 <servlet-name>ProcessServlet</servlet-name>13 <url-pattern>/servlet/ProcessServlet</url-pattern>14 </servlet-mapping>15 16 <welcome-file-list>17 <welcome-file>index.jsp</welcome-file>18 </welcome-file-list>19 </web-app>