public void ProcessRequest(HttpContext context)
        {
            try
            {
                functionName = Query<string>("sys_method", "");
                this.context = context;
                if (functionName.ToLower() == "login" || UserAuth.IsExistsToken(false))
                {
                    p = new Permission(UserAuth.UserName, false);
                    MethodInvoke();
                }
                else
                {
                    WriteError("You haven't log on yet！");
                } 
            }
            catch (Exception err)
            {
                WriteError(err.Message);
            }

            context.Response.End();
        }