我想用lang来标记语言，在认证过程中，这个参数丢失了

Question

http://localhost:8080/auth/login？lang=en我想使用lang标记语言。在身份验证过程中，此参数丢失。我看了源代码。loginurlauthenticationentrypoint.commence```Java公共void开始（HttpServletRequest请求、HttpServletResponse响应、AuthenticationException authException）抛出IOException,ServletException{

    String redirectUrl = null;

    if (useForward) {

        if (forceHttps && "http".equals(request.getScheme())) {
            // First redirect the current request to HTTPS.
            // When that request is received, the forward to the login page will be
            // used.
            redirectUrl = buildHttpsRedirectUrlForRequest(request);
        }

        if (redirectUrl == null) {
            String loginForm = determineUrlToUseForThisRequest(request, response,
                    authException);

            if (logger.isDebugEnabled()) {
                logger.debug("Server side forward to: " + loginForm);
            }

            RequestDispatcher dispatcher = request.getRequestDispatcher(loginForm);

            dispatcher.forward(request, response);

            return;
        }
    }
    else {
        // redirect to login page. Use https if forceHttps true

        redirectUrl = buildRedirectUrlToLoginPage(request, response, authException);

    }

    redirectStrategy.sendRedirect(request, response, redirectUrl);
}

```

Answer 1

用过滤器解决会话中保存消息