private readonly IHostingEnvironment _hostingEnvironment;
        public ExcelController(IHostingEnvironment hostingEnvironment)
        {
            _hostingEnvironment = hostingEnvironment;
        }
[HttpGet("GetFile")]
        public IActionResult GetFile()
        {
            string url = $"{Request.Scheme}://{Request.Host}{Request.PathBase}/file/";
            string path = _hostingEnvironment.ContentRootPath + @"\file\";
            try
            {
                DirectoryInfo dir = new DirectoryInfo(path);
                FileInfo[] finfo = dir.GetFiles();
                string fnames = string.Empty;
                List<ExcelModel> ms = new List<ExcelModel>();
                for (int i = 0; i < finfo.Length; i++)
                {
                    string weburl = url + finfo[i].Name;
                    string fileurl= path + finfo[i].Name;
                    ExcelModel m = new ExcelModel();
                    m.filename= finfo[i].Name;
                    m.intime = finfo[i].CreationTime;
                    //var stream = System.IO.File.OpenRead(fileurl);
                    //m.stream= File(stream, "application/vnd.android.package-archive", Path.GetFileName(fileurl));
                    m.url = weburl;
                    ms.Add(m);
                }
                var response = new
                {
                    code = 20000,
                    data = ms
                };
                return Ok(response);
            }
            catch (Exception)
            {
                throw;
            }
        }