Struts中类型转换报错

Question

今天遇到一个非常郁闷的问题,先看下面代码

 

这个是JSP页面取值代码:

            <td width="102" height="30" align="left"><bean:write name="regediter" property="username"/></td> 
            <td width="81" align="left"><bean:write name="regediter" property="password"/></td>
            <td width="76" align="left"><bean:write name="regediter" property="msn"/></td>
            <td width="68" align="left"><bean:write name="regediter" property="qq"/></td>

 

这个是Action 处理请求代码:

 

 public ActionForward execute(ActionMapping mapping, ActionForm form,
   HttpServletRequest request, HttpServletResponse response) {
  int current = 0 ;
  String id = request.getParameter("id");
  List list ;
  if(id==null){
   list = HibernateDbConnection.getInstance().findById();
  }else{
   list = HibernateDbConnection.getInstance().findById(Integer.valueOf(id));
  }
  Regediter regediter = (Regediter)list;
  request.setAttribute("list", regediter);
  request.setAttribute("current", current);
  return mapping.findForward("success");

 

这个是异常信息:

avax.servlet.ServletException: java.lang.ClassCastException: java.util.ArrayList cannot be cast to customs.zheng.Web.Regediter

我标记的红色字体是错误的关键,寻求解决办法

 

Answer 1

[quote]Regediter regediter = (Regediter)list;[/quote]
这样写肯定不对嘛！
怎么能吧list 转换成一个 Regediter 对象呢？
如果是一个对象的话（因为你是 findbyId）
Regediter regediter = (Regediter)list.get(0);
OK 了 试试