How to pass data from Controller to view in J2ee with spring

I have a simple J2ee application with spring mvc. Now I want to call a method from the jsp page to his controller and I want to have an information from the controller. So I have write this code:

registrazione.jsp

            function saveRigaTable2(){

                try{
                    var nome = document.getElementById("nome").value;
                    var ajaxHandler = new AjaxHandler('POST', '<c:url value="${pageName}"/>.html', false);   
                    ajaxHandler.encodeParameter('method', 'saveItems');
                    ajaxHandler.encodeParameter('nome', nome);

                    ajaxHandler.callbackHandler = function()
                    {           
                        if (ajaxHandler.getRequest().readyState == 4)
                        {   
                            if (ajaxHandler.getRequest().status == 200)
                            {
                                var xmlDoc = ajaxHandler.getRequest().responseXML;

                                var itemsException = xmlDoc.getElementsByTagName("exception");
                                alert(itemsException.length);
                                var items = xmlDoc.getElementsByTagName("registrazioneOK");
                                alert(items.length);
                                if (itemsException.length!=0)
                                {
                                    var punto=itemsException[0];
                                    alert(punto.getAttribute("text"));
                                    document.getElementById("error").innerHTML=punto.getAttribute("text");
                                    alert('Impossibile1 eseguire l\' operazione');
                                }
                                if (items.length!=0)
                                {
                                    var punto=items[0];
                                    alert(punto.getAttribute("text"));
                                }
                            }
                        }
                    };

                    ajaxHandler.startRequest();   
                }
                catch (e)
                {
                    alert('Impossibile eseguire l\' operazione');
                }      
            }
     </script>

This is the method of Controller:

public ModelAndView saveItems(HttpServletRequest request, HttpServletResponse response) throws Exception
    {
        List dataSet = new ArrayList();
        Map dataItem = new HashMap();
        List attributes = new ArrayList();   
        Map model=new HashMap();
        try
        {
            String nome=request.getParameter("nome");
            User user = new User();
            user.setNome(nome);
            if(modelManager.getUserManager().saveUser(user)){
                //request.getSession().setAttribute("rilasciataModificataConf", "SI");
                //registrazione avvenuta con successo
                dataItem.put("tagName", "registrazioneOK");
                attributes.add(new Entity("text", "Complimenti. Registrazione avvenuta con successo." ));
                dataItem.put("attributes", attributes);
                dataSet.add(dataItem);  
                model.put("dataSet", dataSet);
            }


        } catch (Exception e) {
            dataItem.put("tagName", "exception");
            attributes.add(new Entity("text", "Error in saving the current row" ));
            dataItem.put("attributes", attributes);
            dataSet.add(dataItem);  
            model.put("dataSet", dataSet);
            LoggerFactory.logStackTrace(e);
        }
        request.setAttribute("model", model);
        return new ModelAndView("secure/ajax_callback", model);
    }

This is the ajax_callback.jsp

<%@ page contentType="text/xml"%>
<%@ taglib prefix="c" uri="http://ift.tt/QfKAz6"%>
<?xml version="1.0" encoding="iso-8859-1"?>
<dataSet>
   <c:forEach var="dataItem" items="${dataSet}">
        <<c:out value="${dataItem.tagName}"/> 
        <c:forEach var="attribute" items="${dataItem.attributes}">
            <c:out value="${attribute.id}"/>="<c:out value='${attribute.description}'/>" 
        </c:forEach>/>
    </c:forEach>
</dataSet>

When I run this code, I can't read the information, the lenght of the items is all time 0. Where is my error?