登录弹出框

String authorization = (String)request.getHeader("Authorization");
            if (authorization == null) {
                if (allowRetry(session))
                    askForPassword(response);
                else
                    forbidden(response);
                return;
            } 

    private void askForPassword(HttpServletResponse response) 
    {
        response.setStatus(response.SC_UNAUTHORIZED);
        response.setHeader("WWW-Authenticate", "BASIC realm=\"Delivery Tracking System\"");
    }

    private void forbidden(HttpServletResponse response) 
    {
        response.setStatus(response.SC_FORBIDDEN);
    }