ajax|js
提交数据使用json代替xml
页面：jsonExample.jsp
<%@ page contentType="text/html; charset=GBK" %>
<html>
<head>
<title>
JSON示例
</title>
<script type="text/javascript" src="zxml.src.js"></script>
<script type="text/javascript" src="json.js"></script>
<script type="text/javascript">
var xmlHttp;
//创建对象
function createXMLHttpRequest(){
xmlHttp = zXmlHttp.createRequest();
}
function doJSON(){
//得到Car对象
var car = getCarObject();
//用JSON字符串化car对象
var carAsJSON = car.toJSONString();
alert("汽车对象JSON化为:\n" + carAsJSON);
var url = "JSONExample?timeStamp=" + new Date().getTime();
//创建对象
createXMLHttpRequest();
xmlHttp.open("POST",url,true);
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.setRequestHeader("Content-Type","application/x-www-form.urlencoded");
xmlHttp.send(carAsJSON);
}
//回调方法
function handleStateChange(){
if (xmlHttp.readyState == 4){
if (xmlHttp.status == 200){
parseResults();
}
}
}
//解析结果
function parseResults(){
var responseDiv = document.getElementById("serverResponse");
if (responseDiv.hasChildNodes()){
responseDiv.removeChild(responseDiv.childNode[0]);
}
var responseText = document.createTextNode(xmlHttp.responseText);
responseDiv.appendChild(responseText);
}
//得到Car对象
function getCarObject(){
return new Car("Dodge","Coronet R/T",1968,"yellow");
}
//Car构造函数
function Car(make,model,year,color){
this.make = make;
this.model = model;
this.year = year;
this.color = color;
}
</script>
</head>
<body>
<br /><br />
<form action="#">
<input type="button" value="发送JSON数据" />
</form>
<h2>
服务器响应：
</h2>
<div id="serverResponse">
</div>
</body>
</html>
服务器：JSONExample.java
package ajaxbook.chap4;
import java.io.*;
import java.net.*;
import java.text.ParseException;
import javax.servlet.*;
import javax.servlet.http.*;
import org.json.JSONObject;
public class JSONExample
extends HttpServlet {
//处理Post方法
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException,
IOException {
String json = readJSONStringFromRequestBody(request);
//使用JSON绑字Ajax对象
JSONObject jsonObject = null;
try {
jsonObject = new JSONObject(json);
}
catch (ParseException pe) {
System.out.println("ParseException: " + pe.toString());
}
//返回输出结果
String responseText = "You have a " + jsonObject.getInt("year") + " "
+ jsonObject.getString("make") + " " + jsonObject.getString("model")
+ " " + " that is " + jsonObject.getString("color") + " in color.";
response.setContentType("text/xml");
response.getWriter().print(responseText);
}
//得到参数
private String readJSONStringFromRequestBody(HttpServletRequest request) {
StringBuffer json = new StringBuffer();
String line = null;
try {
BufferedReader reader = request.getReader();
while ( (line = reader.readLine()) != null) {
json.append(line);
}
}
catch (Exception e) {
System.out.println("Error reading JSON string: " + e.toString());
}
return json.toString();
}
}
注意：要引入json.js和json的源文件，使用json.jar不行，源文件参见书籍源代码第三章