AJAX+STRUTS+SPRING+hibernate如何实现AJAX直接调用ACTION的方法!,请高人指点

Question

JSP文件定义如下:  <script src='dwr/interface/OnlineNoteAction.js'></script>
  <script src='dwr/engine.js'></script>
  <script src='dwr/util.js'></script>
  <script>
   OnlineNoteManagerImpl.getOnlineNotesOfNotLooked(1);
  </script>
DWR定义如下:<dwr>
    <allow>
       
        <create creator="new" javascript="OnlineNoteAction" class="com.lily.dap.webapp.action.onlinenote.OnlineNoteAction">
          
        </create>
       
   </allow>
</dwr>
ACTION中的方法写法如下:
public ActionForward checkNew(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
if (log.isDebugEnabled()) {
log.debug("检测新消息");
}

long person_id = 1;

OnlineNoteManager onlineNoteManager = (OnlineNoteManager)getBean("onlineNoteManager");
OnlineNote onlineNote = null;

List onlineNoteList = onlineNoteManager.getOnlineNotesOfNotLooked(person_id);
if(onlineNoteList.size() == 0){
  response.setContentType("text/html; charset=gb2312");
        PrintWriter out = response.getWriter();
        out.println("<script type=\"text/javascript\">");
        out.println("alert('您没有新消息!');window.close();");
        out.println("</script>");
return null;

}
request.setAttribute("onlineNoteList", onlineNoteList);
response.setContentType("text/html; charset=gb2312");
        PrintWriter out = response.getWriter();
        
        out.println("<script src=\"scripts/util.js\"></script> ");
        out.println("<script type=\"text/javascript\">");
        out.println("window.location.href=\"./onlineNote.do?method=detail\";");
        out.println("</script>");
        return null;
}调试过程中发现到OnlineNoteManager onlineNoteManager = (OnlineNoteManager)getBean("onlineNoteManager");处报出空指针异常.
其中我的服务层是由接口和实现两部分组成的.