在整合SpringMVC、Spring、Hibernate的时候出现空指针问题

org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:549)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)root cause 
java.lang.NullPointerException
org.apache.jsp.UserList_jsp._jspService(UserList_jsp.java:93)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)在我写查询页面的时候使用了<%
List<User> users = (List<User>)request.getAttribute("users");
for(User u:users){
%>
<tr>
<td><%=u.getU_account() %></td>
<td><%=u.getU_name() %></td>
<td><%=u.getU_telephone() %></td>
<td><%=u.getU_email() %></td>
<!--<td><a href="emp_del.action?id=<%=u.getU_id()%>"
onclick="return confirm('是否要删除<%=u.getU_name()%>');">删除</a>&nbsp;<a
href="emp_update.action?id=<%=u.getU_id()%>">修改</a></td>  -->

</tr>
<%
}
%>
结果他提示我空指针，我翻来覆去看我的代码也没有发现什么问题啊这是controller层的代码@RequestMapping("/administrator_select")
public String Select(HttpSession session) throws Exception{

session.setAttribute("users", administratorServiceDaoImpl.Select());
return "UserList.jsp";这是Service层的代码public List<User> Select()throws Exception{
return userDao.select();
}
这是Dao层的代码@Override
public List<T> select() throws Exception {
// TODO Auto-generated method stub
String hql = "from com.kindacg.entity.User";
Query query = this.getSessionFactory().getCurrentSession().createQuery(hql);
return query.list();
}求大神指点迷津