JSF取服务器端绝动路径

方式一：
HttpSession session = (HttpSession) FacesContext.getCurrentInstance().getExternalContext().getSession(true);
String rootpatch = session.getServletContext().getRealPath("/");
方式二：
public static String getRealPath(String path) 
{ 
        return  ((ServletContext) FacesContext.getCurrentInstance()
.getExternalContext().getContext()).getRealPath(path); 
}