asp.net中四种文件下载方法

     //TransmitFile实现下载      protected void Button1_Click(object sender, EventArgs e)      {          Response.ContentType = "application/x-zip-compressed";          Response.AddHeader("Content-Disposition", "attachment;filename=8月份报表.zip");          string filename = Server.MapPath("DownLoad/8月份报表.zip");          //指定编码 防止中文文件名乱码          Response.HeaderEncoding = System.Text.Encoding.GetEncoding("gb2312");          Response.TransmitFile(filename);      }  

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    //WriteFile实现下载      protected void Button2_Click(object sender, EventArgs e)      {          string fileName = "asd.txt";//客户端保存的文件名          string filePath = Server.MapPath("DownLoad/aaa.txt");//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();      }  

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    //WriteFile分块下载      protected void Button3_Click(object sender, EventArgs e)      {          string fileName = "aaa.txt";//客户端保存的文件名          string filePath = Server.MapPath("DownLoad/aaa.txt");//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();          }      }  

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     //流方式下载      protected void Button4_Click(object sender, EventArgs e)      {          string fileName = "aaa.txt";//客户端保存的文件名          string filePath = Server.MapPath("DownLoad/aaa.txt");//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));          Response.BinaryWrite(bytes);          Response.Flush();          Response.End();      }