Ho risolto!!!
Posto il codice, casomai potesse essere utile ad altri 
Pagina JSP
codice:
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script type="text/javascript" src="<c:url value="/scripts/jquery-1.4.min.js" /> "></script>
<script type="text/javascript" src="<c:url value="/scripts/json.min.js" /> "></script>
<link rel="stylesheet" href="<c:url value="/styles/user-home.css" />" type="text/css" media="screen, projection">
<script type="text/javascript">
$(document).ready(function(){
$("#list").click(function() {
$("#userListForm").hide("slow");
$("#listResult").show("slow");
});
$("#userList").submit(function() {
var userList = $(this).serializeObject();
$.postJSON("userList", userList, function(data) {
var lista = "";
$.each(data, function(i) {
var j = i + 1;
lista = lista + "[*]"+j+"° - "+ data[i] +"";
});
$("#listResult").html("<fieldset><legend>Lista Utenti</legend><ul>"+lista+"[/list]</fieldset>");
});
return false;
});
});
</script>
<title>Welcome <c:out value="${login.username}" /></title>
</head>
<body>
<h3>Benvenuto <c:out value="${login.username}" />!!!</h3>
La tua password è : <c:out value="${login.password}" /></p>
<div id="userListForm">
<form:form id="userList" modelAttribute="userList" action="userList" method="POST">
<fieldset>
<legend>Lista Utenti</legend>
<input id="list" type="submit" value=" Vedi " />
</p>
</fieldset>
</form:form>
</div>
<div id="listResult"></div>
</body>
</html>
Controller
codice:
package org.springframework.samples.mvc.ajax.account;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
@RequestMapping(value = "/userList")
public class UserListController {
@RequestMapping(method = RequestMethod.POST)
public @ResponseBody String[] userList(@RequestBody UserList userList,
HttpServletResponse response){
return userList.getUserList();
}
}
Oggetto UserList
codice:
package org.springframework.samples.mvc.ajax.account;
public class UserList {
String str[] = {"ciccio", "ciccio1", "ciccio2", "ciccio3", "ciccio4"};
public String[] getUserList() {
return str;
}
}
Saluti...