JSP中获取ExtJS.Ajax前台传递的JSON数据实现过程

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.io.BufferedReader" %>
<%@ page import=".sf.json.*" %>
<%
BufferedReader in=request.getReader();
StringBuffer jsonStr=new StringBuffer();
String str="";
while((str=in.readLine())!=null){
jsonStr.append(str);
}
JSONObject jsonObj= JSONObject.fromObject(jsonStr.toString());
String name= jsonObj.getString("userName");
String pwd= jsonObj.getString("passWord");
String msg="";
if(name.equals("Tom")){
msg="登录成功";
}else
{
msg="登录失败";
}
response.getWriter().write(msg);
%>