.参数为虚拟路径

.获取物理地址

.普通下载

.分块下载

.输出硬盘文件，提供下载 支持大文件、续传、速度限制、资源占用小

/// <summary>

/// 编 码 人：苏飞

/// 联系方式：361983679

/// 更新网站：[url=http://www.sufeinet.com/thread-655-1-1.html]http://www.sufeinet.com/thread-655-1-1.html[/url]

/// </summary>

using System;

using System.IO;

using System.Threading;

using System.Web;

namespace DotNet.Utilities

{

    /// <summary>

    /// 文件下载类

    /// </summary>

    public class FileDown

    {

        public FileDown()

        { }

        /// <summary>

        /// 参数为虚拟路径

        /// </summary>

        public static string FileNameExtension(string FileName)

        {

            return Path.GetExtension(MapPathFile(FileName));

        }

        /// <summary>

        /// 获取物理地址

        /// </summary>

        public static string MapPathFile(string FileName)

        {

            return HttpContext.Current.Server.MapPath(FileName);

        }

        /// <summary>

        /// 普通下载

        /// </summary>

        /// <param name="FileName">文件虚拟路径</param>

        public static void DownLoadold(string FileName)

        {

            string destFileName = MapPathFile(FileName);

            if (File.Exists(destFileName))

            {

                FileInfo fi = new FileInfo(destFileName);

                HttpContext.Current.Response.Clear();

                HttpContext.Current.Response.ClearHeaders();

                HttpContext.Current.Response.Buffer = false;

                HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(Path.GetFileName(destFileName), System.Text.Encoding.UTF8));

                HttpContext.Current.Response.AppendHeader("Content-Length", fi.Length.ToString());

                HttpContext.Current.Response.ContentType = "application/octet-stream";

                HttpContext.Current.Response.WriteFile(destFileName);

                HttpContext.Current.Response.Flush();

                HttpContext.Current.Response.End();

            }

        }

        /// <summary>

        /// 分块下载

        /// </summary>

        /// <param name="FileName">文件虚拟路径</param>

        public static void DownLoad(string FileName)

        {

            string filePath = MapPathFile(FileName);

            long chunkSize = ;             //指定块大小

            byte[] buffer = new byte[chunkSize]; //建立一个200K的缓冲区

            long dataToRead = ;                 //已读的字节数

            FileStream stream = null;

            try

            {

                //打开文件

                stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);

                dataToRead = stream.Length;

                //添加Http头

                HttpContext.Current.Response.ContentType = "application/octet-stream";

                HttpContext.Current.Response.AddHeader("Content-Disposition", "attachement;filename=" + HttpUtility.UrlEncode(Path.GetFileName(filePath)));

                HttpContext.Current.Response.AddHeader("Content-Length", dataToRead.ToString());

                while (dataToRead > )

                {

                    if (HttpContext.Current.Response.IsClientConnected)

                    {

                        int length = stream.Read(buffer, , Convert.ToInt32(chunkSize));

                        HttpContext.Current.Response.OutputStream.Write(buffer, , length);

                        HttpContext.Current.Response.Flush();

                        HttpContext.Current.Response.Clear();

                        dataToRead -= length;

                    }

                    else

                    {

                        dataToRead = -; //防止client失去连接

                    }

                }

            }

            catch (Exception ex)

            {

                HttpContext.Current.Response.Write("Error:" + ex.Message);

            }

            finally

            {

                if (stream != null) stream.Close();

                HttpContext.Current.Response.Close();

            }

        }

        /// <summary>

        ///  输出硬盘文件，提供下载 支持大文件、续传、速度限制、资源占用小

        /// </summary>

        /// <param name="_Request">;Page.Request对象</param>

        /// <param name="_Response">;Page.Response对象</param>

        /// <param name="_fileName">下载文件名</param>

        /// <param name="_fullPath">带文件名下载路径</param>

        /// <param name="_speed">每秒允许下载的字节数</param>

        /// <returns>返回是否成功</returns>

        //---------------------------------------------------------------------

        //调用：

        // string FullPath=Server.MapPath("count.txt");

        // ResponseFile(this.Request,this.Response,"count.txt",FullPath,100);

        //---------------------------------------------------------------------

        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 = ;

                    int pack = ;  //10K bytes

                    int sleep = (int)Math.Floor((double)( * pack / _speed)) + ;

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

                    {

                        _Response.StatusCode = ;

                        string[] range = _Request.Headers["Range"].Split(new char[] { '=', '-' });

                        startBytes = Convert.ToInt64(range[]);

                    }

                    _Response.AddHeader("Content-Length", (fileLength - startBytes).ToString());

                    if (startBytes != )

                    {

                        _Response.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, fileLength - , 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((double)((fileLength - startBytes) / pack)) + ;

                    for (int i = ; 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;

        }

    }

}