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最新推荐文章于 2024-07-18 16:16:57 发布

原创最新推荐文章于 2024-07-18 16:16:57 发布 · 977 阅读

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#exception #buffer #string #byte #null

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此博客展示了一个名为 ResponseFile 的公共静态布尔方法代码。该方法接收请求、响应、文件名、完整路径和速度等参数，实现文件响应功能。通过文件流和二进制读取器处理文件，添加响应头信息，处理字节范围，使用字节缓冲区传输数据，同时包含异常处理。

public static bool ResponseFile( System.Web.HttpRequest _Request,
           System.Web.HttpResponse _Response,
           string _fileName,string _fullPath, long _speed)
  {
   try
   {
    FileStream myFile = new FileStream(_fullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
    BinaryReader br = new BinaryReader(myFile);
    try
    {
     _Response.AddHeader("Accept-Ranges", "bytes");
     _Response.Buffer = false;
     long fileLength = myFile.Length;
     long startBytes = 0;

     int pack = 10240; //10K bytes
     if (_Request.Headers["Range"] != null)
     {
      _Response.StatusCode = 206;
      string[] range = _Request.Headers["Range"].Split(new char[] {'=', '-'});
      startBytes = Convert.ToInt64(range[1]);
     }
     _Response.AddHeader("Content-Length", (fileLength - startBytes).ToString());
     if (startBytes != 0)
     {
      _Response.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, fileLength-1, fileLength));
     }
     _Response.AddHeader("Connection", "Keep-Alive");
     _Response.ContentType = "application/octet-stream";
     _Response.AddHeader("Content-Disposition","attachment;filename=" + System.Web.HttpUtility.UrlEncode(_fileName,System.Text.Encoding.UTF8) );

     br.BaseStream.Seek(startBytes, SeekOrigin.Begin);
     int maxCount = (int) Math.Floor((fileLength - startBytes) / pack) + 1;
     byte[] buffer=new byte[pack];

     for (int i = 0; i < maxCount; i++)
     {
      if (_Response.IsClientConnected)
      {
       buffer=br.ReadBytes(pack);
       _Response.OutputStream.Write(buffer, 0, pack);
       _Response.Flush();
       buffer=new byte[pack];

      }
      else
      {
       i=maxCount;
      }
     }
    }
    catch(Exception myerror)
    {
     throw myerror;
    }
    finally
    {
     br.Close();
     myFile.Close();
    }
   }
   catch(Exception myerror)
   {
    throw myerror;
   }
   return true;
  }