api下载文件

net 

       /// <summary>
       ///字符流下载方法
       /// </summary>
       /// <param name="fileName">下载文件生成的名称</param>
       /// <param name="fPath">下载文件路径</param>
       /// <returns></returns>
        public void DownloadFile(string fileName, string fPath)
        {
            string filePath = Server.MapPath(fPath);//路径
            //以字符流的形式下载文件
            FileStream fs = new FileStream(filePath, FileMode.Open);
            byte[] bytes = new byte[(int)fs.Length];
            fs.Read(bytes, 0, bytes.Length);
            fs.Close();
            Response.ContentType = "application/octet-stream";
            //通知浏览器下载文件而不是打开
            Response.AddHeader("Content-Disposition", "attachment;   filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
           // 添加头信息，指定文件大小，让浏览器能够显示下载进度
           Response.AddHeader("Content-Length", file.Length.ToString());

            Response.BinaryWrite(bytes);
            Response.Flush();
            Response.End();
        }

WriteFile实现下载 

string fileName ="aaa.zip";//客户端保存的文件名 
  string filePath=Server.MapPath("DownLoad/aaa.zip");//路径 

  FileInfo fileInfo = new FileInfo(filePath); 
  Response.Clear(); 
  Response.ClearContent(); 
  Response.ClearHeaders(); 
  Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName); 
  Response.AddHeader("Content-Length", fileInfo.Length.ToString()); 
  Response.AddHeader("Content-Transfer-Encoding", "binary"); 
  Response.ContentType = "application/octet-stream"; 
  Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312"); 
  Response.WriteFile(fileInfo.FullName); 
  Response.Flush(); 
  Response.End(); 

Response.TransmitFile(filePath);

WriteFile分块下载 

string fileName = "aaa.zip";//客户端保存的文件名 
  string filePath = Server.MapPath("DownLoad/aaa.zip");//路径 

  System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath); 

  if (fileInfo.Exists == true) 
  { 
  const long ChunkSize = 102400;//100K 每次读取文件，只读取100Ｋ，这样可以缓解服务器的压力 
  byte[] buffer = new byte[ChunkSize]; 

  Response.Clear(); 
  System.IO.FileStream iStream = System.IO.File.OpenRead(filePath); 
  long dataLengthToRead = iStream.Length;//获取下载的文件总大小 
  Response.ContentType = "application/octet-stream"; 
  Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName)); 
  while (dataLengthToRead > 0 && Response.IsClientConnected)  
  { 
  int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小 
  Response.OutputStream.Write(buffer, 0, lengthRead); 
  Response.Flush(); 
  dataLengthToRead = dataLengthToRead - lengthRead; 
  } 
  Response.Close(); 
  } 

WEBAPI

        public HttpResponseMessage DownloadByPath(string filePath)
        {
            try
            {
                if (!File.Exists(filePath))
                {
                    filePath = MapPath(filePath);
                    if (!File.Exists(filePath))
                    {
                        throw new HttpResponseException(HttpStatusCode.NotFound);
                    }
                }

                FileStream fileStream = new FileStream(filePath, FileMode.Open);
                HttpResponseMessage fullResponse = Request.CreateResponse(HttpStatusCode.OK);
                fullResponse.Content = new StreamContent(fileStream);

                MediaTypeHeaderValue _mediaType = MediaTypeHeaderValue.Parse("application/octet-stream");//指定文件类型
                ContentDispositionHeaderValue _disposition = ContentDispositionHeaderValue.Parse("attachment;filename=" + System.Web.HttpUtility.UrlEncode(Path.GetFileName(filePath)));//指定文件名称 System.Web.HttpUtility.UrlEncode 不加失败

                fullResponse.Content.Headers.ContentType = _mediaType;
                fullResponse.Content.Headers.ContentDisposition = _disposition;
                return fullResponse;
            }
            catch (Exception ex)
            {
                Logger.Error(ex);
                throw new HttpResponseException(HttpStatusCode.NotFound);
            }
        }

 System.Web.HttpUtility.UrlEncode 出错更改

fullResponse.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment") { FileName = docName };

                        var url = API接口;
                        let link = document.createElement('a');
                        link.href = url;
                        link.target = "_blank";
                        link.click();
                        window.URL.revokeObjectURL(link.href);

API 传输数据加密