using System.IO; using System.Threading;
// 輸出硬盤文件,提供下載 支持大文件、續傳、速度限制、資源佔用小 // 輸入參數 _Request: Page.Request對象, _Response: Page.Response對象, _fileName: 下載文件名, _fullPath: 帶文件名下載路徑, _speed 每秒允許下載的字節數 // 返回是否成功 public static bool ResponseFile(HttpRequest _Request,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 //int sleep = 200; //每秒5次 即5*10K bytes每秒 int sleep = (int)Math.Floor(1000 * pack / _speed) + 1; 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=" + HttpUtility.UrlEncode(_fileName,System.Text.Encoding.UTF8) ); br.BaseStream.Seek(startBytes, SeekOrigin.Begin); int maxCount = (int) Math.Floor((fileLength - startBytes) / pack) + 1;
for (int i = 0; i < maxCount; i++) { if (_Response.IsClientConnected) { _Response.BinaryWrite(br.ReadBytes(pack)); Thread.Sleep(sleep); } else { i=maxCount; } } } catch { return false; } finally { br.Close(); myFile.Close(); } } catch { return false; } return true; }
調用例
Page.Response.Clear(); bool success = ResponseFile(Page.Request, Page.Response, "filename", @"C:/download.date", 1024000); if(!success) Response.Write("下載文件出錯!");
Page.Response.End();
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