类型转换异常：java.lang.ClassCastException

大家帮忙看下：
代码：
public ActionForward update(ActionMapping mapping,ActionForm form,
HttpServletRequest request,HttpServletResponse response){
// TODO Auto-generated method stub
Long id=Long.valueOf((String)request.getParameter("id"));
//List list=(List)infoDao.findById(id);

UserInfo userInfo=infoDao.findById(id);

request.setAttribute("userInfo",userInfo);
request.setAttribute("id",id);

return new ActionForward("/update.jsp");
}
update.Jsp:
<%
List list=(List)request.getAttribute("userInfo");错误应该就在这两行
UserInfo info=(UserInfo)list.get(0);
String id=(String)request.getAttribute("id");
String name=info.getName();
String age=String.valueOf(info.getAge());  out.println(age);
//String age="aaa";
if(age.equals("null")) age="";
String tel=info.getTel(); if(tel==null) tel="";
String qq=info.getQq(); if(qq==null) qq="";
String email=info.getEmail(); if(email==null) email="";
String sex=info.getSex(); if(sex==null) sex="";
String birthday=DateTools.dateToString(info.getBirthday()); if(birthday==null) birthday="";
String home=info.getHome(); if(home==null) home="";
out.print(name+tel+qq+email+sex+home);
request.setCharacterEncoding("UTF-8");
request.setAttribute("id",id);
%>
=============================JSP报错信息如下：==============================
description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:372)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1063)
org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:386)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:229)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:174)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:75)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
root cause java.lang.ClassCastException
org.apache.jsp.update_jsp._jspService(update_jsp.java:89)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1063)
org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:386)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:229)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:174)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:75)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)