为什么无法查询到数据解决方法

package com.test.action;import java.util.Map;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;import com.test.service.Iservice;public class ListUserAction extends ActionSupport{    private Iservice service;    public Iservice getService()    {        return service;    }    public void setService(Iservice service)    {        this.service = service;    }            @SuppressWarnings("unchecked")    @Override    public String execute() throws Exception    {        Map request = (Map) ActionContext.getContext().get("request");        request.put("list",service.listUser());                return SUCCESS;    }    }

       <s:iterator value="#request.list" id="us">               <tr>               <td><s:property value="#us.id"/>               </td>                              <td><s:property value="#us.firstname"/>               </td>                              <td><s:property value="#us.lastname"/>               </td>                              <td><s:property value="#us.age"/>               </td>         </tr>       </s:iterator>

    public List<User> listUser()    {        String hql = "from User user order by user.id desc";        return (List<User>)this.getHibernateTemplate().find(hql);    }