JSP迭代SESSION对象

<%
 ReturnVO e = (ReturnVO)request.getSession().getAttribute("retVO");
  if(e!=null)
  {
  Enumeration c = session.getAttributeNames();
  
  while(c.hasMoreElements()){
%>
	<%
		String name = (String)c.nextElement();
		out.print(name);
	 %>
<%
	}
	 List retVOList = (List)e.getretVO();
	if(e.getretVO()!=null)
	{
%>
<%
 	  out.print("e.getretVO(): "+retVOList.size());
 }else{
 	out.print("successful: ");
%>
<%}}%>