Struts2和json报错 Could not find action or result

struts.xml
  <package name="tt"  namespace="/"  extends="json-default">        <action name="remessage" class="com.softeem.action.JsonAction">
           <result type="json" name="success"></result>
        </action>
   </package>
index.jsp
<script type="text/javascript"  language="javascript">
   var request=null;
   function getConn(url,back){
   if(window.XMLHttpRequest){
    request=new XMLHttpRequest();
   }else if(window.ActiveXObject){
   request=new ActiveXObject("Micrsoft.XMLHTTP");
   }
   request.open("GET",url,true);
   request.onreadystatechange=back;
   request.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
   request.setRequestHeader("If-Modified-Since","0");
   request.send(null);
      }
      
      function message(){
      if(request.readystate==4){
        if(reqeust.state==200){
        var Obj=eval('('+request.responseText+')');
         alert("---------"+Obj);
        }
      }
 }
</script>