例子来源:《Ajax 基础教程》 金灵 等译 这本书非常不错
postingXML.html
PostingXMLExample.java
postingXML.html
<html>
<head>
<title></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 createXML() {
var xml = "<pets>";
var options = document.getElementById("petTypes").childNodes;
var option = null;
for(var i = 0; i < options.length; i++) {
option = options[i];
if(option.selected) {
xml = xml + "<type>" + option.value + "<\/type>";
}
}
xml = xml + "<\/pets>";
return xml;
}
function sendPetTypes() {
createXMLHttpRequest();
var xml = createXML();
var url = "PostingXMLExample?timeStamp=" + new Date().getTime();
xmlHttp.open("POST", url, true);
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;");
xmlHttp.send(xml);
}
function handleStateChange() {
if(xmlHttp.readyState == 4) {
if(xmlHttp.status == 200) {
parseResults();
}
}
}
function parseResults() {
var responseDiv = document.getElementById("serverResponse");
if (responseDiv.hasChildNodes()) {
responseDiv.removeChild(responseDiv.childNodes[0]);
}
var responseText = document.createTextNode(xmlHttp.responseText);
responseDiv.appendChild(responseText);
}
</script>
</head>
<body>
<h1>Select the types of pets in your home: </h1>
<form action="#" >
<select id="petTypes" size="6" multiple="true">
<option value="cats">cats</option>
<option value="dogs">dogs</option>
<option value="fish">fish</option>
<option value="birds">birds</option>
<option value="hamsters">hamsters</option>
<option value="rabbits">rabbits</option>
</select>
<br /><br />
<input type="button" value="submit Pets" onclick="sendPetTypes();" />
<h2>Server Response:</h2>
<div id="serverResponse"></div>
</form>
</body>
</html>
PostingXMLExample.java
package ajaxbook.chap3;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class PostingXMLExample extends HttpServlet {
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
String xml = readXMLFromRequestBody(request);
Document xmlDoc = null;
try {
xmlDoc = DocumentBuilderFactory.newInstance().newDocumentBuilder()
.parse(new ByteArrayInputStream(xml.getBytes()));
}
catch(ParserConfigurationException e) {
System.out.println("ParserConfigurationException: " + e);
}
catch(SAXException e) {
System.out.println("SAXException: " + e);
}
NodeList selectedPetTypes = xmlDoc.getElementsByTagName("type");
String type = null;
String responseText = "selected Pets: ";
for(int i = 0; i < selectedPetTypes.getLength(); i++) {
type = selectedPetTypes.item(i).getFirstChild().getNodeValue();
responseText = responseText + " " + type;
}
response.setContentType("text/xml");
response.getWriter().print(responseText);
}
private String readXMLFromRequestBody(HttpServletRequest request) {
StringBuffer xml = new StringBuffer();
String line = null;
try {
BufferedReader reader = request.getReader();
while((line = reader.readLine()) != null) {
xml.append(line);
}
}
catch(Exception e) {
System.out.println("Error reading XML: " + e.toString());
}
return xml.toString();
}
}