JSF 取 Session

FacesContext facesContext = FacesContext.getCurrentInstance();
HttpSession session = (HttpSession) facesContext.getExternalContext().getSession(false);
Enumeration e = session.getAttributeNames();
while (e.hasMoreElements())
{
String attr = (String)e.nextElement();
System.err.println(" attr = "+ attr);
Object value = session.getValue(attr);
System.err.println(" value = "+ value);
}