关于下载的东西 解释下 谢谢

Question

Response.Clear(); Response.ClearContent(); Response.ClearHeaders(); stringurlName = HttpUtility.UrlEncode(f.f_filename,System.Text.Encoding.UTF8);Response.AddHeader("Content-Disposition", "attachment;filename=" + urlName);Response.AddHeader("Content-Length", info.Length.ToString());Response.AddHeader("Content-Transfer-Encoding", "binary"); Response.ContentType= "application/octet-stream"; Response.ContentEncoding =System.Text.Encoding.GetEncoding("gb2312"); Response.WriteFile(info.FullName);Response.Flush(); Response.End();每个response 的什么意思都 ？？？？