Netty + jQuery , use url + query string is ok , but use JQuery receive nothing?

my web side html code like this

$.ajax({

type : "Get",

url : "http://localhost:9999",

data : {"servicename" :"test"},

timeout:100000,

beforeSend: function(xhr) { 

             },

success: function(rs) {

        alert("[success]"  + rs);

      },

complete:function(XMLHttpRequest,textStatus){

              if(XMLHttpRequest.readyState=="4"){

                  alert("response text= " + XMLHttpRequest.responseText);

              }

              },  

     error: function(XMLHttpRequest,textStatus,errorThrown){

              alert("error:"+textStatus);

          }       

});

I Use url querystring ( http://localhost:9999?servicename="test" ) can receive data ,but i use jquery reveive nothing. jquery version is 1.4. Netty Server is run example HttpSnoopServer.java.