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  • C# 文件下载工具类FileDownHelper

    using System;
    using System.IO;
    using System.Threading;
    using System.Web;
    
    namespace 落地页测试代码
    {
        public class FileDownHelper
        {
            public FileDownHelper()
            { }
            public static string FileNameExtension(string FileName)
            {
                return Path.GetExtension(MapPathFile(FileName));
            }
            public static string MapPathFile(string FileName)
            {
                return HttpContext.Current.Server.MapPath(FileName);
            }
            public static bool FileExists(string FileName)
            {
                string destFileName = FileName;
                if (File.Exists(destFileName))
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            public static void DownLoadold(string FileName, string name)
            {
                string destFileName = 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(name, 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();
                }
            }
            public static void DownLoad(string FileName)
            {
                string filePath = MapPathFile(FileName);
                long chunkSize = 204800;             //指定块大小 
                byte[] buffer = new byte[chunkSize]; //建立一个200K的缓冲区 
                long dataToRead = 0;                 //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 > 0)
                    {
                        if (HttpContext.Current.Response.IsClientConnected)
                        {
                            int length = stream.Read(buffer, 0, Convert.ToInt32(chunkSize));
                            HttpContext.Current.Response.OutputStream.Write(buffer, 0, length);
                            HttpContext.Current.Response.Flush();
                            HttpContext.Current.Response.Clear();
                            dataToRead -= length;
                        }
                        else
                        {
                            dataToRead = -1; //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();
                }
            }
            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 = (int)Math.Floor((double)(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((double)((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;
            }
        }
    }
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  • 原文地址:https://www.cnblogs.com/bin521/p/10569635.html
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