使用Ajax显示进度条
使用Ajax显示进度条
1.进度条由DIV框和数个有背景颜色的SPAN组成；
2.初始化时DIV不可见，SPAN背景色与网页背景色一致；
3.根据服务器返回的进度百分比，计算出应显示几个SPAN块，并为SPAN块设置背景色；
progressBar.html:
程序代码
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>ProgressBar</title>
<script type="text/javascript" src="js/progressBar.js"></script>
</head>
<body>
<h1>Ajax Progress Bar</h1>
<input id="btn" type="button" value="Start" onClick="doStart();" />
<br /><br />
<div id="bar" style="width:156px; border:#000000 2px solid; padding:1px; visibility:hidden;">
<span id="bar1" style="background-color:#FFFFFF"> </span>
<span id="bar2" style="background-color:#FFFFFF"> </span>
<span id="bar3" style="background-color:#FFFFFF"> </span>
<span id="bar4" style="background-color:#FFFFFF"> </span>
<span id="bar5" style="background-color:#FFFFFF"> </span>
<span id="bar6" style="background-color:#FFFFFF"> </span>
<span id="bar7" style="background-color:#FFFFFF"> </span>
<span id="bar8" style="background-color:#FFFFFF"> </span>
<span id="bar9" style="background-color:#FFFFFF"> </span>
<span id="bar10" style="background-color:#FFFFFF"> </span>
</div>
<br />
<div id="result"></div>
</body>
</html>
progressBar.js:
程序代码
var xmlHttp;
function createXMLHttpRequest() {
if (window.ActiveXObject) {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} else if (window.XMLHttpRequest) {
xmlHttp = new XMLHttpRequest();
}
}
function doStart() {
init();
document.getElementById("bar").style.visibility = "visible";
}
function init() {
createXMLHttpRequest();
xmlHttp.onreadystatechange = handleChange;
var url = "progressBar.mgc?action=init×tamp=" + new Date().getTime();
xmlHttp.open("GET", url, true);
xmlHttp.send(null);
}
function handleChange() {
if (xmlHttp.readyState == 4) {
if (xmlHttp.status == 200) {
refresh();
}
}
}
function refresh() {
createXMLHttpRequest();
xmlHttp.onreadystatechange = callback;
var url = "progressBar.mgc?action=run×tamp=" + new Date().getTime();
xmlHttp.open("GET", url, true);
xmlHttp.send(null);
setTimeout("refresh()", "500");
}
function callback() {
if (xmlHttp.readyState == 4) {
if (xmlHttp.status == 200) {
parseResult();
}
}
}
function parseResult() {
var xmlDoc = xmlHttp.responseXML;
var pros = xmlDoc.getElementsByTagName("progress");
var result = "";
for (var i = 0; i < pros.length; i++) {
var massage = pros[i].childNodes[0].childNodes[0].nodeValue;
var percent = pros[i].childNodes[1].childNodes[0].nodeValue;
result += massage + "[" + percent + "%]" + "<br />";
}
document.getElementById("result").innerHTML = result;
clearBar();
var percents = xmlDoc.getElementsByTagName("percent");
var nowPercent = percents[percents.length - 1].childNodes[0].nodeValue;
var count = parseInt(nowPercent / 10);
for (var i = 0; i <= count; i++) {
if (i != 0) {
var bar = document.getElementById("bar" + i);
bar.style.backgroundColor = "#bababa";
}
}
}
function clearBar() {
for (var i = 1; i <= 10; i++) {
var bar = document.getElementById("bar" + i);
bar.style.backgroundColor = "#FFFFFF";
}
}
progressBar.java:
程序代码
package cn.edu.ahau.mgc.ajax.progressbar;
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 ProgressBar extends HttpServlet {
private int count;
private StringBuffer str;
public static final int TOTAL = 25;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String action = request.getParameter("action");
if ("init".equals(action)) {
this.count = 1;
this.str = new StringBuffer();
} else if ("run".equals(action)) {
if (this.count <= TOTAL) {
int percent = count * 100 / TOTAL;
str.append("<progress><massage>完成了 " + (this.count++) + "个任务</massage><percent>" + percent + "</percent></progress>");
}
response.setContentType("text/xml; charset=UTF-8");
response.setHeader("Cache-Control", "no-cache");
PrintWriter out = response.getWriter();
out.print("<response>" + str + "</response>");
out.flush();
out.close();
}
}
}
web.xml:
程序代码
<?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>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>ProgressBar</servlet-name>
<servlet-class>cn.edu.ahau.mgc.ajax.progressbar.ProgressBar</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ProgressBar</servlet-name>
<url-pattern>/progressBar.mgc</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
1.进度条由DIV框和数个有背景颜色的SPAN组成；
2.初始化时DIV不可见，SPAN背景色与网页背景色一致；
3.根据服务器返回的进度百分比，计算出应显示几个SPAN块，并为SPAN块设置背景色；
progressBar.html:
程序代码
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>ProgressBar</title>
<script type="text/javascript" src="js/progressBar.js"></script>
</head>
<body>
<h1>Ajax Progress Bar</h1>
<input id="btn" type="button" value="Start" onClick="doStart();" />
<br /><br />
<div id="bar" style="width:156px; border:#000000 2px solid; padding:1px; visibility:hidden;">
<span id="bar1" style="background-color:#FFFFFF"> </span>
<span id="bar2" style="background-color:#FFFFFF"> </span>
<span id="bar3" style="background-color:#FFFFFF"> </span>
<span id="bar4" style="background-color:#FFFFFF"> </span>
<span id="bar5" style="background-color:#FFFFFF"> </span>
<span id="bar6" style="background-color:#FFFFFF"> </span>
<span id="bar7" style="background-color:#FFFFFF"> </span>
<span id="bar8" style="background-color:#FFFFFF"> </span>
<span id="bar9" style="background-color:#FFFFFF"> </span>
<span id="bar10" style="background-color:#FFFFFF"> </span>
</div>
<br />
<div id="result"></div>
</body>
</html>
progressBar.js:
程序代码
var xmlHttp;
function createXMLHttpRequest() {
if (window.ActiveXObject) {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} else if (window.XMLHttpRequest) {
xmlHttp = new XMLHttpRequest();
}
}
function doStart() {
init();
document.getElementById("bar").style.visibility = "visible";
}
function init() {
createXMLHttpRequest();
xmlHttp.onreadystatechange = handleChange;
var url = "progressBar.mgc?action=init×tamp=" + new Date().getTime();
xmlHttp.open("GET", url, true);
xmlHttp.send(null);
}
function handleChange() {
if (xmlHttp.readyState == 4) {
if (xmlHttp.status == 200) {
refresh();
}
}
}
function refresh() {
createXMLHttpRequest();
xmlHttp.onreadystatechange = callback;
var url = "progressBar.mgc?action=run×tamp=" + new Date().getTime();
xmlHttp.open("GET", url, true);
xmlHttp.send(null);
setTimeout("refresh()", "500");
}
function callback() {
if (xmlHttp.readyState == 4) {
if (xmlHttp.status == 200) {
parseResult();
}
}
}
function parseResult() {
var xmlDoc = xmlHttp.responseXML;
var pros = xmlDoc.getElementsByTagName("progress");
var result = "";
for (var i = 0; i < pros.length; i++) {
var massage = pros[i].childNodes[0].childNodes[0].nodeValue;
var percent = pros[i].childNodes[1].childNodes[0].nodeValue;
result += massage + "[" + percent + "%]" + "<br />";
}
document.getElementById("result").innerHTML = result;
clearBar();
var percents = xmlDoc.getElementsByTagName("percent");
var nowPercent = percents[percents.length - 1].childNodes[0].nodeValue;
var count = parseInt(nowPercent / 10);
for (var i = 0; i <= count; i++) {
if (i != 0) {
var bar = document.getElementById("bar" + i);
bar.style.backgroundColor = "#bababa";
}
}
}
function clearBar() {
for (var i = 1; i <= 10; i++) {
var bar = document.getElementById("bar" + i);
bar.style.backgroundColor = "#FFFFFF";
}
}
progressBar.java:
程序代码
package cn.edu.ahau.mgc.ajax.progressbar;
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 ProgressBar extends HttpServlet {
private int count;
private StringBuffer str;
public static final int TOTAL = 25;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String action = request.getParameter("action");
if ("init".equals(action)) {
this.count = 1;
this.str = new StringBuffer();
} else if ("run".equals(action)) {
if (this.count <= TOTAL) {
int percent = count * 100 / TOTAL;
str.append("<progress><massage>完成了 " + (this.count++) + "个任务</massage><percent>" + percent + "</percent></progress>");
}
response.setContentType("text/xml; charset=UTF-8");
response.setHeader("Cache-Control", "no-cache");
PrintWriter out = response.getWriter();
out.print("<response>" + str + "</response>");
out.flush();
out.close();
}
}
}
web.xml:
程序代码
<?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>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>ProgressBar</servlet-name>
<servlet-class>cn.edu.ahau.mgc.ajax.progressbar.ProgressBar</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ProgressBar</servlet-name>
<url-pattern>/progressBar.mgc</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>