winform多线程分块下载文件 ----分享

javaoraspx 2014-01-17 04:23:11

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 public class DownloadThread

    { 

        private string saveFilePath;

        private Uri downUrl;

        private long block;

        private int threadId = -1;

        private long downLength;

        private bool finish = false;

        private FileDownloader downloader;



        public DownloadThread(FileDownloader downloader, Uri downUrl, string saveFile, long block, long downLength, int threadId)

        {

            this.downUrl = downUrl;

            this.saveFilePath = saveFile;

            this.block = block;

            this.downloader = downloader;

            this.threadId = threadId;

            this.downLength = downLength;

        }





        public void ThreadRun()

        {

            //task

            Thread td = new Thread(new ThreadStart(() =>

            {

                Console.WriteLine(threadId.ToString() + " start  " + downLength.ToString() + "      " + block.ToString());

                if (downLength < block)//未下载完成

                {

                    try

                    {

                        int startPos = (int)(block * (threadId - 1) + downLength);//开始位置

                        int endPos = (int)(block * threadId - 1);//结束位置

                        Console.WriteLine("Thread " + this.threadId + " start download from position " + startPos + "  and endwith " + endPos);

                        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(downUrl);

                        request.Referer = downUrl.ToString();

                        request.Method = "GET";

                        request.UserAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; SV1; .NET CLR 2.0.1124)";

                        request.AllowAutoRedirect = false;

                        request.ContentType = "application/octet-stream";

                        request.Accept = "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*";

                        request.Timeout = 10 * 1000;

                        request.AllowAutoRedirect = true; 

                        request.AddRange(startPos, endPos);

                        //Console.WriteLine(request.Headers.ToString());

                        HttpWebResponse response = (HttpWebResponse)request.GetResponse();

                        WebResponse wb = request.GetResponse();

                        using (Stream _stream = wb.GetResponseStream())

                        { 

                            byte[] buffer = new byte[1024 * 50];

                            long offset = -1;

                            using (Stream threadfile = new FileStream(this.saveFilePath, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite))

                            {

                                threadfile.Seek(startPos, SeekOrigin.Begin);

                                while ((offset = _stream.Read(buffer, 0, buffer.Length)) != 0)

                                {

                                    downloader.append(offset); 

                                    threadfile.Write(buffer, 0, (int)offset);

                                    downLength += offset;

                                    downloader.update(this.threadId, downLength);

                                }

                                threadfile.Close();

                                _stream.Close();

                                Console.WriteLine("Thread " + this.threadId + " download finish");

                                this.finish = true;

                            }

                        }

                    }

                    catch (Exception e)

                    {

                        this.downLength = -1;

                        Console.WriteLine("Thread " + this.threadId + ":" + e.Message);

                    }

                }

                else

                {

                    Console.WriteLine(downLength);

                }

            }));

            td.IsBackground = true;

            td.Start();

        }

        /// <summary>

        /// 下载是否完成

        /// </summary>

        /// <returns></returns>

        public bool isFinish()

        {

            return finish;

        }

        /// <summary> 

        ///  已经下载的内容大小 ;return 如果返回值为-1,代表下载失败

        /// </summary>

        /// <returns></returns>

        public long getDownLength()

        {

            return downLength;

        }



    }