JSF(Java Server Face) 框架中如何获取传统的HttpSession或HttpServletRequest对象

为了保持向后兼容，我们有时可能会需要访问session对象。在JSF中可以通过如下方式来获取session.

HttpSession session = (ServletContext)FacesContext.getCurrentInstance().getExternalContext().getSession(false);

获取request对象的方式也比较相似

HttpServletRequest request = (HttpServletRequest)FacesContext.getCurrentInstance().getExternalContext().getRequest();