public ActionResult GetAccessToken(int client_id, string client_secret, string grant_type)
        {
            return(Invoke(() =>
            {
                CheckOAuthParam(client_id, client_secret, grant_type);

                //TODO: 这里去调用适当的方法去获取系统内用户的ID
                var userId = 10000;
                var accessToken = AccessTokenService.CreateAccessToken(userId, client_id);
                HttpContext.Items["userId"] = userId;

                return new
                {
                    access_token = accessToken.Token,
                    expires_in = accessToken.Expire,
                    userId = userId
                };
            }));
        }