1.dynamicLists.html：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Dynamically Filling Lists</title>
<script type="text/javascript">
var xmlHttp;
function createXMLHttpRequest() {
if (window.ActiveXObject) {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
else if (window.XMLHttpRequest) {
xmlHttp = new XMLHttpRequest();
}
}
function refreshModelList() {
var make = document.getElementById("make").value;
var modelYear = document.getElementById("modelYear").value;
if(make == "" || modelYear == "") {
clearModelsList();
return;
}
var url = "RefreshModelList?"
+ createQueryString(make,modelYear) + "&ts=" + new Date().getTime();
createXMLHttpRequest();
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.open("GET",url,true);
xmlHttp.send(null);
}
function createQueryString(make,modelYear) {
var queryString = "make=" + make + "&modelYear=" + modelYear;
return queryString;
}
function handleStateChange() {
if(xmlHttp.readyState == 4) {
if(xmlHttp.status == 200) {
updateModelsList();
}
}
}
function updateModelsList() {
clearModelsList();
var models = document.getElementById("models");
var results = xmlHttp.responseXML.getElementsByTagName("model");
var option = null;
for(var i = 0; i < results.length; i++) {
option = document.createElement("option");
option.appendChild(document.createTextNode(results[i].firstChild.nodeValue));
models.appendChild(option);
}
}
function clearModelsList() {
var models = document.getElementById("models");
while(models.childNodes.length > 0) {
models.removeChild(models.childNodes[0]);
}
}
</script>
</head>
<body>
<h1>Select Model Year and Make</h1>
<form action="#">
<span style="font-weight:bold;">Model Year:</span>
<select id="modelYear" onchange="refreshModelList();">
<option value="">Select One</option>
<option value="2006">2006</option>
<option value="1995">1995</option>
<option value="1985">1985</option>
<option value="1970">1970</option>
</select>
<br/><br/>
<span style="font-weight:bold;">Make:</span>
<select id="make" onchange="refreshModelList();">
<option value="">Select One</option>
<option value="Chevrolet">Chevrolet</option>
<option value="Dodge">Dodge</option>
<option value="Pontiac">Pontiac</option>
</select>
<br/><br/>
<span style="font-weight:bold;">Models:</span>
<br/>
<select id="models" size="6" style="width:300px;">
</select>
</form>
</body>
</html>
2.RefreshModelListServlet.java:
package com.wch.ajax.servlet;
import java.io.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.servlet.*;
import javax.servlet.http.*;
public class RefreshModelListServlet extends HttpServlet {
private static List availableModels = new ArrayList();
protected void processRequest(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException {
response.setContentType("text/html;charset=UTF-8");
int modelYear = Integer.parseInt(request.getParameter("modelYear"));
String make = request.getParameter("make");
StringBuffer results = new StringBuffer("<models>");
MakeModelYear availableModel = null;
for(Iterator it = availableModels.iterator(); it.hasNext();) {
availableModel = (MakeModelYear)it.next();
if(availableModel.modelYear == modelYear) {
if(availableModel.make.equals(make)) {
results.append("<model>");
results.append(availableModel.model);
results.append("</model>");
}
}
}
results.append("</models>");
response.setContentType("text/xml");
response.getWriter().write(results.toString());
}
protected void doGet(HttpServletRequest request,IOException {
processRequest(request,response);
}
public void init() throws ServletException {
availableModels.add(new MakeModelYear(2006,"Dodge","Charger"));
availableModels.add(new MakeModelYear(2006,"Magnum"));
availableModels.add(new MakeModelYear(2006,"Ram"));
availableModels.add(new MakeModelYear(2006,"Viper"));
availableModels.add(new MakeModelYear(1995,"Avenger"));
availableModels.add(new MakeModelYear(1995,"Intrepid"));
availableModels.add(new MakeModelYear(1995,"Neon"));
availableModels.add(new MakeModelYear(1995,"Spirit"));
availableModels.add(new MakeModelYear(1985,"Aries"));
availableModels.add(new MakeModelYear(1985,"Daytona"));
availableModels.add(new MakeModelYear(1985,"Diplomat"));
availableModels.add(new MakeModelYear(1985,"Omni"));
availableModels.add(new MakeModelYear(1970,"Challenger"));
availableModels.add(new MakeModelYear(1970,"Charger"));
availableModels.add(new MakeModelYear(1970,"Coronet"));
availableModels.add(new MakeModelYear(1970,"Dart"));
availableModels.add(new MakeModelYear(2006,"Chevrolet","Colorado"));
availableModels.add(new MakeModelYear(2006,"Corvette"));
availableModels.add(new MakeModelYear(2006,"Equinox"));
availableModels.add(new MakeModelYear(2006,"Monte Carlo"));
availableModels.add(new MakeModelYear(1995,"Beretta"));
availableModels.add(new MakeModelYear(1995,"Camaro"));
availableModels.add(new MakeModelYear(1995,"Cavalier"));
availableModels.add(new MakeModelYear(1995,"Lumina"));
availableModels.add(new MakeModelYear(1985,"Cavalier"));
availableModels.add(new MakeModelYear(1985,"Chevette"));
availableModels.add(new MakeModelYear(1985,"Celebrity"));
availableModels.add(new MakeModelYear(1985,"Citation II"));
availableModels.add(new MakeModelYear(1970,"Bel Air"));
availableModels.add(new MakeModelYear(1970,"Caprice"));
availableModels.add(new MakeModelYear(1970,"Chevelle"));
availableModels.add(new MakeModelYear(1970,"Monte Carlo"));
availableModels.add(new MakeModelYear(2006,"Pontiac","G6"));
availableModels.add(new MakeModelYear(2006,"Grand Prix"));
availableModels.add(new MakeModelYear(2006,"Solstice"));
availableModels.add(new MakeModelYear(2006,"Vibe"));
availableModels.add(new MakeModelYear(1995,"Bonneville"));
availableModels.add(new MakeModelYear(1995,"Grand Am"));
availableModels.add(new MakeModelYear(1995,"Grand Prix"));
availableModels.add(new MakeModelYear(1995,"Firebird"));
availableModels.add(new MakeModelYear(1985,"6000"));
availableModels.add(new MakeModelYear(1985,"Fiero"));
availableModels.add(new MakeModelYear(1985,"Grand Prix"));
availableModels.add(new MakeModelYear(1985,"Parisienne"));
availableModels.add(new MakeModelYear(1970,"Catalina"));
availableModels.add(new MakeModelYear(1970,"GTO"));
availableModels.add(new MakeModelYear(1970,"LeMans"));
availableModels.add(new MakeModelYear(1970,"Tempest"));
}
private static class MakeModelYear {
private int modelYear;
private String make;
private String model;
public MakeModelYear(int modelYear,String make,String model) {
this.modelYear = modelYear;
this.make = make;
this.model = model;
}
}
}
3.web.xml:
<servlet>
<servlet-name>RefreshModelListServlet</servlet-name>
<servlet-class>com.wch.ajax.servlet.RefreshModelListServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>RefreshModelListServlet</servlet-name>
<url-pattern>/RefreshModelList</url-pattern>
</servlet-mapping>
4.运行结果是：
原文链接：https://www.f2er.com/ajax/166612.html
