快速解决owin返回json字符串多带了双引号

 [HttpGet]    public HttpResponseMessage getsystemtime()    {      cltime time = new cltime();      time.datetime = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");      string relsut = JsonConvert.SerializeObject(time);      var resp = new HttpResponseMessage { Content = new StringContent(relsut, System.Text.Encoding.UTF8, "application/json") };      return resp;    }