asp.net下载，支持中文名，断点续传，控制单线程下载速度

参考：http://blog.csdn.net/Teng_s2000/archive/2005/10/21/510857.aspx

　　　/article/4634889.html

using System;

using System.Data;

using System.Configuration;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.IO;

namespace lianxi

{

public class Download

{

public Download()

{

}

public static void DownloadFile(HttpResponse Response, HttpRequest Request, string filepath, int speed)

{

if (!File.Exists(filepath))

{

Response.StatusCode = 404; //http状态代码，具体请看http://hi.baidu.com/%C3%AB%CE%D1/blog/item/7066a154993750133b2935ab.html

return;

}

string name = Path.GetFileName(filepath); //获取文件名

int packSize = 10240;

byte[] buffer = new byte[packSize];

long fileLength;

long startByets = 0;

FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);

BinaryReader br = new BinaryReader(fs);

fileLength = fs.Length;

int sleep = (int)Math.Ceiling(1000.0 * packSize / speed); //用于单线程控制下载速度

try

{

Response.Clear();

Response.ClearHeaders();

Response.Buffer = false;

if (Request.Headers["Range"] != null)

{

Response.StatusCode = 206; //这个续传是必备的

startByets = long.Parse(Request.Headers["Range"].Replace("bytes=", "").Replace("-", "")); //获取客户端已经下载的字节数

}

if (startByets != 0)

{

Response.AddHeader("Content-Range", string.Format("bytes {0}-{1}/{2}", startByets, fileLength - 1, fileLength)); //续传必备，表示客户端从哪个字节开始下载，到哪个字节结束下载，具体请看http://hi.baidu.com/%C3%AB%CE%D1/blog/item/a630dfd3c18dbbd3a8ec9afc.html中的“Content-Range”，注意“fileLength
- 1”，这是有点像数组，用文件的长度-1就可以得到数组的最后字节了。

}

Response.AddHeader("Content-Length", fileLength.ToString()); //告诉客户端所要下载文件的长度

Response.AddHeader("Accept-Ranges", "bytes"); //续传必备

Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(name, System.Text.Encoding.UTF8));//用于支持英文文件名

Response.ContentType = "application/octet-stream"; //一般是这个，这个请看http://baike.baidu.com/view/160611.htm（MIME百科）

Response.ContentEncoding = System.Text.Encoding.UTF8;

fs.Seek(startByets, SeekOrigin.Begin);//设置文件流的起点位置

int maxCount = (int)Math.Ceiling((fileLength - startByets + 0.0) / packSize);

for (int i = 0; i < maxCount && Response.IsClientConnected; i++)

{

//int length = fs.Read(buffer, 0, packSize);

//Response.OutputStream.Write(buffer, 0, packSize);

Response.BinaryWrite(br.ReadBytes(packSize));

Response.Flush();

if (sleep > 0) System.Threading.Thread.Sleep(sleep);

}

}

catch (Exception ex)

{

Response.Write(ex.Message);

}

finally

{

fs.Close();

}

}

}

}

2

// 输出硬盘文件，提供下载

// 输入参数 _Request: Page.Request对象， _Response: Page.Response对象， _fileName: 下载文件名， _fullPath: 带文件名下载路径， _speed 每秒允许下载的字节数

// 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;

}

调用例

Page.Response.Clear();

bool success = ResponseFile(Page.Request, Page.Response, "filename", @"C:/download.date", 1024000);

if(!success)

Response.Write("下载文件出错！");

Page.Response.End();