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Ajax打造Web进度条

2013-07-16 
Ajax制作Web进度条1 %@ page languagejava pageEncodingUTF-8%2 !DOCTYPE HTML PUBLIC -//W3C//

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 = "&nbsp;&nbsp;&nbsp;"; //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&nbsp;&nbsp;&nbsp;<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">&nbsp;&nbsp;&nbsp;</span>121                <span id="sp1">&nbsp;&nbsp;&nbsp;</span>122                <span id="sp2">&nbsp;&nbsp;&nbsp;</span>123                <span id="sp3">&nbsp;&nbsp;&nbsp;</span>124                <span id="sp4">&nbsp;&nbsp;&nbsp;</span>125                <span id="sp5">&nbsp;&nbsp;&nbsp;</span>126                <span id="sp6">&nbsp;&nbsp;&nbsp;</span>127                <span id="sp7">&nbsp;&nbsp;&nbsp;</span>128                <span id="sp8">&nbsp;&nbsp;&nbsp;</span>129                <span id="sp9">&nbsp;&nbsp;&nbsp;</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>

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