Ajax動態載入列表框
阿新 • • 發佈:2019-02-10
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, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
public void init() throws ServletException {
availableModels.add(new MakeModelYear(2006, "Dodge", "Charger"));
availableModels.add(new MakeModelYear(2006, "Dodge", "Magnum"));
availableModels.add(new MakeModelYear(2006, "Dodge", "Ram"));
availableModels.add(new MakeModelYear(2006, "Dodge", "Viper"));
availableModels.add(new MakeModelYear(1995, "Dodge", "Avenger"));
availableModels.add(new MakeModelYear(1995, "Dodge", "Intrepid"));
availableModels.add(new MakeModelYear(1995, "Dodge", "Neon"));
availableModels.add(new MakeModelYear(1995, "Dodge", "Spirit"));
availableModels.add(new MakeModelYear(1985, "Dodge", "Aries"));
availableModels.add(new MakeModelYear(1985, "Dodge", "Daytona"));
availableModels.add(new MakeModelYear(1985, "Dodge", "Diplomat"));
availableModels.add(new MakeModelYear(1985, "Dodge", "Omni"));
availableModels.add(new MakeModelYear(1970, "Dodge", "Challenger"));
availableModels.add(new MakeModelYear(1970, "Dodge", "Charger"));
availableModels.add(new MakeModelYear(1970, "Dodge", "Coronet"));
availableModels.add(new MakeModelYear(1970, "Dodge", "Dart"));
availableModels.add(new MakeModelYear(2006, "Chevrolet", "Colorado"));
availableModels.add(new MakeModelYear(2006, "Chevrolet", "Corvette"));
availableModels.add(new MakeModelYear(2006, "Chevrolet", "Equinox"));
availableModels.add(new MakeModelYear(2006, "Chevrolet", "Monte Carlo"));
availableModels.add(new MakeModelYear(1995, "Chevrolet", "Beretta"));
availableModels.add(new MakeModelYear(1995, "Chevrolet", "Camaro"));
availableModels.add(new MakeModelYear(1995, "Chevrolet", "Cavalier"));
availableModels.add(new MakeModelYear(1995, "Chevrolet", "Lumina"));
availableModels.add(new MakeModelYear(1985, "Chevrolet", "Cavalier"));
availableModels.add(new MakeModelYear(1985, "Chevrolet", "Chevette"));
availableModels.add(new MakeModelYear(1985, "Chevrolet", "Celebrity"));
availableModels.add(new MakeModelYear(1985, "Chevrolet", "Citation II"));
availableModels.add(new MakeModelYear(1970, "Chevrolet", "Bel Air"));
availableModels.add(new MakeModelYear(1970, "Chevrolet", "Caprice"));
availableModels.add(new MakeModelYear(1970, "Chevrolet", "Chevelle"));
availableModels.add(new MakeModelYear(1970, "Chevrolet", "Monte Carlo"));
availableModels.add(new MakeModelYear(2006, "Pontiac", "G6"));
availableModels.add(new MakeModelYear(2006, "Pontiac", "Grand Prix"));
availableModels.add(new MakeModelYear(2006, "Pontiac", "Solstice"));
availableModels.add(new MakeModelYear(2006, "Pontiac", "Vibe"));
availableModels.add(new MakeModelYear(1995, "Pontiac", "Bonneville"));
availableModels.add(new MakeModelYear(1995, "Pontiac", "Grand Am"));
availableModels.add(new MakeModelYear(1995, "Pontiac", "Grand Prix"));
availableModels.add(new MakeModelYear(1995, "Pontiac", "Firebird"));
availableModels.add(new MakeModelYear(1985, "Pontiac", "6000"));
availableModels.add(new MakeModelYear(1985, "Pontiac", "Fiero"));
availableModels.add(new MakeModelYear(1985, "Pontiac", "Grand Prix"));
availableModels.add(new MakeModelYear(1985, "Pontiac", "Parisienne"));
availableModels.add(new MakeModelYear(1970, "Pontiac", "Catalina"));
availableModels.add(new MakeModelYear(1970, "Pontiac", "GTO"));
availableModels.add(new MakeModelYear(1970, "Pontiac", "LeMans"));
availableModels.add(new MakeModelYear(1970, "Pontiac", "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>