c# 檔案的斷點續傳

標籤：drop   mode   image   format   emd   pen   obj   用戶端   split   

一、開篇描述

本篇部落格所描述的斷點續傳功能是基於c#語言，伺服器端採用.net mvc架構，用戶端採用winform架構。

本篇部落格實現斷點續傳功能的基本思路：1）伺服器端是把已接收的檔案流，追加到已有的檔案；2）用戶端是把檔案流截段上傳；

其實，任何一種電腦語言基於這個思路，都可以實現斷點續傳的功能。

二、伺服器端

namespace MvcApp.Controllers{    public class HomeController : Controller    {        //        // GET: /Home/        public ActionResult Index()        {            //string ip = Request.UserHostAddress;            //string port = Request.ServerVariables["REMOTE_PORT"].ToString();            return View();        }        /// <summary>        /// 擷取續傳點。        /// </summary>        /// <param name="md5Name"></param>        /// <returns></returns>        public string GetFileResumePoint(string md5Name)        {            var saveFilePath = Server.MapPath("~/Images/") + md5Name;            if (System.IO.File.Exists(saveFilePath))            {                var fs = System.IO.File.OpenWrite(saveFilePath);                var fsLength = fs.Length.ToString();                fs.Close();                return fsLength;            }            return "0";        }        /// <summary>        /// 檔案續傳。        /// </summary>        /// <returns></returns>        [HttpPost]        public HttpResponseMessage FileResume()        {            var fileStream = Request.InputStream;            var md5Name = Request.QueryString["md5Name"];            SaveAs(Server.MapPath("~/Images/") + md5Name, fileStream);            return new HttpResponseMessage(HttpStatusCode.OK);        }        /// <summary>        /// 給已有檔案追加檔案流。        /// </summary>        /// <param name="saveFilePath"></param>        /// <param name="stream"></param>        private void SaveAs(string saveFilePath, System.IO.Stream stream)        {            //接收到的位元組資訊。            long startPosition = 0;            long endPosition = 0;            var contentRange = Request.Headers["Content-Range"];//contentRange範例：bytes 10000-20000/59999            if (!string.IsNullOrEmpty(contentRange))            {                contentRange = contentRange.Replace("bytes", "").Trim();                contentRange = contentRange.Substring(0, contentRange.IndexOf("/"));                string[] ranges = contentRange.Split(‘-‘);                startPosition = long.Parse(ranges[0]);                endPosition = long.Parse(ranges[1]);            }            //預設寫針位置。            System.IO.FileStream fs;            long writeStartPosition = 0;            if (System.IO.File.Exists(saveFilePath))            {                fs = System.IO.File.OpenWrite(saveFilePath);                writeStartPosition = fs.Length;            }            else            {                fs = new System.IO.FileStream(saveFilePath, System.IO.FileMode.Create);            }            //調整寫針位置。            if (writeStartPosition > endPosition)            {                fs.Close();                return;            }            else if (writeStartPosition < startPosition)            {                fs.Close();                return;            }            else if (writeStartPosition > startPosition && writeStartPosition < endPosition)            {                writeStartPosition = startPosition;            }            fs.Seek(writeStartPosition, System.IO.SeekOrigin.Current);            //向檔案追加檔案流。            byte[] nbytes = new byte[512];            int nReadSize = 0;            nReadSize = stream.Read(nbytes, 0, 512);            while (nReadSize > 0)            {                fs.Write(nbytes, 0, nReadSize);                nReadSize = stream.Read(nbytes, 0, 512);            }            fs.Close();        }    }}

　　

三、用戶端

1 介面如下：

2 代碼如下：

namespace WindowsFormsApplication1{    public partial class Form1 : Form    {        /// <summary>        /// 定義委託。        /// </summary>        /// <param name="text"></param>        delegate void ChangeText(string text);        /// <summary>        /// 暫停標記。        /// </summary>        int flag = 0;        /// <summary>        /// 上傳的檔案路徑。        /// </summary>        string filePath;        /// <summary>        /// 上傳的檔案md5值。        /// </summary>        string md5Str;        /// <summary>        /// 上傳的檔案續傳點。        /// </summary>        long startPoint;        public Form1()        {            InitializeComponent();        }        /// <summary>        /// 委託方法。        /// </summary>        /// <param name="text"></param>        public void ChangeLabelText(string text)        {            this.label1.Text = text;        }        /// <summary>        /// 得到檔案的MD5值。        /// </summary>        /// <param name="filePath"></param>        /// <returns></returns>        public string GetFileMd5(string filePath)        {            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();            FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);            Byte[] hashBytes = md5.ComputeHash(fs);            fs.Close();            return BitConverter.ToString(hashBytes).Replace("-", "");        }        /// <summary>        /// 得到檔案的續傳點。        /// </summary>        /// <param name="md5Str"></param>        /// <param name="fileExtension"></param>        /// <returns></returns>        public long GetFileResumePoint(string md5Str, string fileExtension)        {            System.Net.WebClient webClient = new System.Net.WebClient();            string urlStr = "http://file.taiji.com/Home/GetFileResumePoint?md5Name=" + md5Str + fileExtension;            byte[] infoBytes = webClient.DownloadData(urlStr);            string result = System.Text.Encoding.UTF8.GetString(infoBytes);            if (string.IsNullOrEmpty(result))            {                return 0;            }            return Convert.ToInt64(result);        }        public void ResumeFileThread()        {            MessageBox.Show(ResumeFile("http://file.taiji.com/Home/FileResume", filePath, startPoint, 1024 * 128, md5Str));        }        public string ResumeFile(string hostUrl, string filePath, long startPoint, int byteCount, string md5Str)        {            string result = "上傳成功！";            byte[] data;            System.Net.WebClient webClient = new System.Net.WebClient();            FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);            long fileLength = fs.Length;            BinaryReader bReader = new BinaryReader(fs);            try            {                #region 續傳處理                if (startPoint == fileLength)                {                    result = "檔案秒傳！";                }                if (startPoint >= 1 && startPoint <= fileLength - 1)                {                    fs.Seek(startPoint, SeekOrigin.Current);                }                #endregion                #region 分割檔案上傳                for (; startPoint <= fileLength - 1; startPoint = startPoint + byteCount)                {                    int step = 0;                    if (startPoint + byteCount > fileLength)                    {                        data = new byte[Convert.ToInt32(fileLength - startPoint)];                        bReader.Read(data, 0, Convert.ToInt32(fileLength - startPoint));                        step = Convert.ToInt32(fileLength - startPoint);                    }                    else                    {                        data = new byte[byteCount];                        bReader.Read(data, 0, byteCount);                        step = byteCount;                    }                    webClient.Headers.Remove(HttpRequestHeader.ContentRange);                    webClient.Headers.Add(HttpRequestHeader.ContentRange, "bytes " + startPoint + "-" + (startPoint + step) + "/" + fs.Length);                    webClient.UploadData(hostUrl + "?md5Name=" + md5Str + Path.GetExtension(filePath), "POST", data);                    this.BeginInvoke(new ChangeText(ChangeLabelText), (startPoint + step) + "/" + fileLength);                pause:                    if (flag == 1)                    {                        Thread.Sleep(1000);                        goto pause;                    }                }                #endregion            }            catch (Exception ex)            {                result = ex.Message;            }            bReader.Close();            fs.Close();            return result;        }        /// <summary>        /// 上傳按鈕點擊事件。        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void button1_Click(object sender, EventArgs e)        {            OpenFileDialog openFileDialog = new OpenFileDialog();            if (openFileDialog.ShowDialog() == DialogResult.OK)            {                filePath = openFileDialog.FileName;                md5Str = GetFileMd5(filePath);                startPoint = GetFileResumePoint(md5Str, Path.GetExtension(filePath));                ThreadStart ts = new ThreadStart(ResumeFileThread);                Thread t = new Thread(ts);                t.Start();            }        }        /// <summary>        /// 暫停按鈕點擊事件。        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void button2_Click(object sender, EventArgs e)        {            flag = 1;        }        /// <summary>        /// 繼續按鈕點擊事件。        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void button3_Click(object sender, EventArgs e)        {            flag = 0;        }        /// <summary>        /// 允許拖拽。        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void Form1_Load(object sender, EventArgs e)        {            this.AllowDrop = true;        }        /// <summary>        /// 拖拽上傳。        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void Form1_DragOver(object sender, DragEventArgs e)        {            if (e.Data.GetDataPresent(DataFormats.FileDrop))            {                string[] files = e.Data.GetData(DataFormats.FileDrop) as string[];                MessageBox.Show("準備上傳" + files.Length + "個檔案！");                foreach (string file in files)                {                    MessageBox.Show("開始上傳檔案：" + file);                    filePath = file;                    md5Str = GetFileMd5(filePath);                    startPoint = GetFileResumePoint(md5Str, Path.GetExtension(filePath));                    ThreadStart ts = new ThreadStart(ResumeFileThread);                    Thread t = new Thread(ts);                    t.Start();                }            }        }    }}

　　

c# 檔案的斷點續傳