ajax json

                         JSONObject的使用
    1. 要使程序可以运行必须引入JSON-lib包，JSON-lib包同时依赖于以下的JAR包：

      commons-lang.jar

      commons-beanutils.jar

      commons-collections.jar

      commons-logging.jar

      ezmorph.jar

      json-lib-2.2.2-jdk15.jar

     2. 前台js代码

       $(document).ready(function(){
  $("#b01").click(function(){
  $.ajax({
             type: "post",
             url: "ajaxs.html",
             data: {username:"xiaoming", content:"jiji"},
             dataType: "text",
          success: function(data){
                       alert(data);
                       var jsonList = eval("("+data+")");
var begin =jsonList.begin;
var end = jsonList.end;
var span = jsonList.span;
var str = jsonList.str;
alert(begin+end+span+str);
                 },
                 error: function(json)
                 {
                 alert("获取信息失败！");
                 }
         });
});
});
         3. 后台代码
        @RequestMapping("/ajaxs")
public void ajaxs(HttpServletRequest request,HttpServletResponse response){

System.out.println(request.getParameter("username"));
System.out.println(request.getParameter("content"));
try {
PrintWriter pw = response.getWriter();
JSONObject jsonObj = new JSONObject();
jsonObj.put("str", "ss1");
jsonObj.put("begin", "ss2");
jsonObj.put("end", "ss3");
jsonObj.put("span", "ss4");
pw.print(jsonObj.toString());
} catch (IOException e) {
e.printStackTrace();
}

}