public final class SelAction extends Action{
     private Set set  = new HashSet();
     public ActionForward execute(......){
            String fname = request.getParameter("fname");
            if(fname != null){
                 set.add(fname);
            }
            session.setAttribute("sfile",set);
            
    }
在显示的页面里
<logic:iterator name = "sfile"  scope = "session">
   <bean:write name ="sfile"/>
</logic:iterator>

在loginout的Action里
public final class LoginoutAction extends Action{
     public ActionForward execute(......){
         ...  
          session.removeAttribute("sfile");
         ...   
    }
}