• asp.net 实现下载的几种方法


    protected void Button1_Click(object sender, EventArgs e)
      {
      /*
      微软为Response对象提供了一个新的方法TransmitFile来解决使用Response.BinaryWrite
      下载超过400mb的文件时导致Aspnet_wp.exe进程回收而无法成功下载的问题。
      代码如下:
      */

      Response.ContentType = "application/x-zip-compressed";
      Response.AddHeader("Content-Disposition", "attachment;filename=z.zip");
      string filename = Server.MapPath("DownLoad/aaa.zip");
      Response.TransmitFile(filename);
      }

      //WriteFile实现下载
      protected void Button2_Click(object sender, EventArgs e)
      {
      /*
      using System.IO;
        
      */

      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();
      }

      //WriteFile分块下载
      protected void Button3_Click(object sender, EventArgs e)
      {

      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();
      }
      }

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

      } 
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  • 原文地址:https://www.cnblogs.com/shuchun/p/2535040.html
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