Asp.net 2.0 文件下载[支持多线程, 断点续传功能](示例代码下载)-优快云博客

(一) . 概述

最近做了个C/S文件下载工具, 支持多任务, 多线程和断点续传功能. 其中部分代码是从网上找来的, 自己改了

许多Thread Bug, 并增加多任务, 断点续传等功能.

由于公司具有代码所有权, 不能将源代码共享. 自己对比较Asp.net感兴趣, 业余时间自己做了个简单的, 基于

Asp.net 2.0的, 目前能够执行对一个文件的下载任务, 但已经实现了多线程, 断点续传功能. 根据需要您可以增加

多任务功能, 分享一下, 互相学习! 互相借鉴!

时间仓促, 此程序还没有做很多参数方面的优化. 可以作参考用.

(二).运行效果

(三). 代码

1. 核心 DownLoadState.cs 文件代码

   1 /// <summary>
   2 /// Author: [ ChengKing(ZhengJian) ]
   3 /// Blog:   Http://blog.youkuaiyun.com/ChengKing
   4 /// 注：从网上找了个优秀代码
   5 /// 扩展如下功能:
   6 ///    1. 解决一些线程相关的Bug;
   7 ///    2.扩展用控制文件实现断点续传功能.
   8 /// </summary>
   9 namespace DownLoadComponent
  10 {
  11      /// <summary>
  12      /// 多线程辅助类(Add by ChengKing)
  13      /// </summary>
  14      public class Task
  15     {
  16          string _FromFileName;
  17          string _ToFileName;
  18          int _ThreadNum;
  19
  20          public Task( string FromFileName, string ToFileName, int ThreadNum)
  21         {
  22              this ._FromFileName = FromFileName;
  23              this ._ToFileName = ToFileName;
  24              this ._ThreadNum = ThreadNum;
  25         }
  26
  27          public string FromFileName
  28         {
  29              get
  30             {
  31                  return _FromFileName;
  32             }
  33              set
  34             {
  35                 _FromFileName = value;
  36             }
  37         }
  38          public string ToFileName
  39         {
  40              get
  41             {
  42                  return _ToFileName;
  43             }
  44              set
  45             {
  46                 _ToFileName = value;
  47             }
  48         }
  49          public int ThreadNum
  50         {
  51              get
  52             {
  53                  return _ThreadNum;
  54             }
  55              set
  56             {
  57                 _ThreadNum = value;
  58             }
  59         }
  60     }
  61
  62      /// <summary>
  63      /// 记录下载的字节位置
  64      /// </summary>
  65      public class DownLoadState
  66     {
  67          private string _FileName;
  68
  69          private string _AttachmentName;
  70          private int _Position;
  71          private string _RequestURL;
  72          private string _ResponseURL;
  73          private int _Length;
  74
  75          private byte [] _Data;
  76
  77          public string FileName
  78         {
  79              get
  80             {
  81                  return _FileName;
  82             }
  83         }
  84
  85          public int Position
  86         {
  87              get
  88             {
  89                  return _Position;
  90             }
  91         }
  92
  93          public int Length
  94         {
  95              get
  96             {
  97                  return _Length;
  98             }
  99         }
100
101
102          public string AttachmentName
103         {
104              get
105             {
106                  return _AttachmentName;
107             }
108         }
109
110          public string RequestURL
111         {
112              get
113             {
114                  return _RequestURL;
115             }
116         }
117
118          public string ResponseURL
119         {
120              get
121             {
122                  return _ResponseURL;
123             }
124         }
125
126
127          public byte [] Data
128         {
129              get
130             {
131                  return _Data;
132             }
133         }
134
135          internal DownLoadState( string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length, byte [] Data)
136         {
137              this ._FileName = FileName;
138              this ._RequestURL = RequestURL;
139              this ._ResponseURL = ResponseURL;
140              this ._AttachmentName = AttachmentName;
141              this ._Position = Position;
142              this ._Data = Data;
143              this ._Length = Length;
144         }
145
146          internal DownLoadState( string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length, ThreadCallbackHandler tch)
147         {
148              this ._RequestURL = RequestURL;
149              this ._ResponseURL = ResponseURL;
150              this ._FileName = FileName;
151              this ._AttachmentName = AttachmentName;
152              this ._Position = Position;
153              this ._Length = Length;
154              this ._ThreadCallback = tch;
155         }
156
157          internal DownLoadState( string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length)
158         {
159              this ._RequestURL = RequestURL;
160              this ._ResponseURL = ResponseURL;
161              this ._FileName = FileName;
162              this ._AttachmentName = AttachmentName;
163              this ._Position = Position;
164              this ._Length = Length;
165         }
166
167          private ThreadCallbackHandler _ThreadCallback;
168
169          //
170          internal void StartDownloadFileChunk()
171         {
172              if ( this ._ThreadCallback != null )
173             {
174                  this ._ThreadCallback( this ._RequestURL, this ._FileName, this ._Position, this ._Length);
175             }
176         }
177
178     }
179
180      // 委托代理线程的所执行的方法签名一致
181      public delegate void ThreadCallbackHandler( string S, string s, int I, int i);
182
183      // 异常处理动作
184      public enum ExceptionActions
185     {
186         Throw,
187         CancelAll,
188         Ignore,
189         Retry
190     }
191
192      /// <summary>
193      /// 包含 Exception 事件数据的类
194      /// </summary>
195      public class ExceptionEventArgs : System.EventArgs
196     {
197          private System.Exception _Exception;
198          private ExceptionActions _ExceptionAction;
199
200          private DownLoadState _DownloadState;
201
202          public DownLoadState DownloadState
203         {
204              get
205             {
206                  return _DownloadState;
207             }
208         }
209
210          public Exception Exception
211         {
212              get
213             {
214                  return _Exception;
215             }
216         }
217
218          public ExceptionActions ExceptionAction
219         {
220              get
221             {
222                  return _ExceptionAction;
223             }
224              set
225             {
226                 _ExceptionAction = value;
227             }
228         }
229
230          internal ExceptionEventArgs(System.Exception e, DownLoadState DownloadState)
231         {
232              this ._Exception = e;
233              this ._DownloadState = DownloadState;
234         }
235     }
236
237      /// <summary>
238      /// 包含 DownLoad 事件数据的类
239      /// </summary>
240      public class DownLoadEventArgs : System.EventArgs
241     {
242          private DownLoadState _DownloadState;
243
244          public DownLoadState DownloadState
245         {
246              get
247             {
248                  return _DownloadState;
249             }
250         }
251
252          public DownLoadEventArgs(DownLoadState DownloadState)
253         {
254              this ._DownloadState = DownloadState;
255         }
256
257     }
258
259      /// <summary>
260      /// 支持断点续传多线程下载的类
261      /// </summary>
262      public class HttpWebClient
263     {
264          private static object _SyncLockObject = new object ();
265
266          public delegate void DataReceiveEventHandler(HttpWebClient Sender, DownLoadEventArgs e);
267
268          public event DataReceiveEventHandler DataReceive; // 接收字节数据事件
269
270          public delegate void ExceptionEventHandler(HttpWebClient Sender, ExceptionEventArgs e);
271
272          public event ExceptionEventHandler ExceptionOccurrs; // 发生异常事件
273
274          private int _FileLength; // 下载文件的总大小
275
276          public static ArrayList threads;
277
278          public int FileLength
279         {
280              get
281             {
282                  return _FileLength;
283             }
284         }
285
286          /// <summary>
287          /// 分块下载文件
288          /// </summary>
289          /// <param name="Address"> URL 地址 </param>
290          /// <param name="FileName"> 保存到本地的路径文件名 </param>
291          /// <param name="ChunksCount"> 块数,线程数 </param>
292          public void DownloadFile( string Address, string FileName, int ChunksCount)
293         {
294              int p = 0 ; // position
295              int s = 0 ; // chunk size
296              string a = null ;
297             HttpWebRequest hwrq;
298             HttpWebResponse hwrp = null ;
299              try
300             {
301
302                 hwrq = (HttpWebRequest)WebRequest.Create( this .GetUri(Address));
303                  // hwrq.Timeout = 20000000;
304                  // if (hwrq.HaveResponse == false)
305                  //     return;
306                  // hwrq.ProtocolVersion =HttpVersion.Version10;
307                  // WebProxy wp = WebProxy.GetDefaultProxy();
308                  // hwrq.Proxy = wp;
309                 hwrq.Method = " GET " ;
310                  try
311                 {
312                     hwrp = (HttpWebResponse)hwrq.GetResponse();
313                 }
314                  catch (Exception e)
315                 {
316                      throw new Exception(e.Message);
317                 }
318
319                  long L = hwrp.ContentLength;
320
321                  // 如果文件太小, 就不用分多线程, 用一个线程下载即可. (目前控制在800K)
322                  // if (L < 800000)
323                  // {
324                  //     ChunksCount = 1;
325                  // }
326
327                 hwrq.Credentials = this .m_credentials;
328
329                 L = ((L == - 1 ) || (L > 0x7fffffff )) ? (( long ) 0x7fffffff ) : L; // Int32.MaxValue 该常数的值为 2,147,483,647; 即十六进制的 0x7FFFFFFF
330
331                  int l = ( int )L;
332
333                  this ._FileLength = l;
334
335                  bool b = (hwrp.Headers[ " Accept-Ranges " ] != null & hwrp.Headers[ " Accept-Ranges " ] == " bytes " );
336                 a = hwrp.Headers[ " Content-Disposition " ]; // attachment
337                  if (a != null )
338                 {
339                     a = a.Substring(a.LastIndexOf( " filename= " ) + 9 );
340                 }
341                  else
342                 {
343                     a = FileName;
344                 }
345
346                  int ss = s;
347                  if (b)
348                 {
349                      if (ExistControlFile(FileName)) // 是否存在文件
350                     {
351                          string [] strBlocks = this .ReadInfFromControlFile(FileName).Split( new char [ 2 ] { ' \r ' , ' \n ' });
352                          for ( int i = 0 ; i < strBlocks.Length; i ++ )
353                         {
354                              if (strBlocks[i].Trim().Length != 0 && strBlocks[i].Substring(strBlocks[i].Length - 1 ) == " 0 " )
355                             {
356                                  string [] strRecord = strBlocks[i].Split( ' , ' );
357                                  int p2 = int .Parse(strRecord[ 0 ]);
358                                  int s2 = int .Parse(strRecord[ 1 ]);
359                                 DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, p2, s2, new ThreadCallbackHandler( this .DownloadFileChunk));
360                                 Thread t = new Thread( new ThreadStart(x.StartDownloadFileChunk));
361                                  if (threads == null )
362                                 {
363                                     threads = new ArrayList();
364                                 }
365                                 threads.Add(t);
366                                 t.Start();
367                             }
368
369
370                         }
371
372                     }
373                      else
374                     {
375                          // 建立控制文件
376                         FileStream fs = File.Create( this .GetControlFileName(FileName));
377                         fs.Close();
378
379                          if (File.Exists(FileName))
380                         {
381                             FileInfo fi = new FileInfo(FileName);
382                              if (fi.Length == L)
383                             {
384                                  this .AddendInfToControlFile(FileName, 0 , 0 );
385                                  this .UpdateControlFile(FileName, 0 , 0 );
386                                  return ;
387                             }
388                         }
389
390                         s = l / ChunksCount;
391                          if (s < 2 * 64 * 1024 ) // 块大小至少为 128 K 字节
392                         {
393                             s = 2 * 64 * 1024 ;
394                         }
395                         ss = s;
396                          int i = 0 ;
397                          while (l >= s)
398                         {
399                             l -= s;
400                              if (l < s)
401                             {
402                                 s += l;
403                             }
404                              if (i ++ > 0 )
405                             {
406                                 DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, p, s, new ThreadCallbackHandler( this .DownloadFileChunk));
407
408                                 AddendInfToControlFile(FileName, p, s);
409                                 Thread t = new Thread( new ThreadStart(x.StartDownloadFileChunk));
410                                  if (threads == null )
411                                 {
412                                     threads = new ArrayList();
413                                 }
414                                 threads.Add(t);
415                                 t.Start();
416
417                             }
418                             p += s;
419                         }
420                         s = ss;
421
422                         AddendInfToControlFile(FileName, 0 , s);
423                         DownLoadState x1 = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, 0 , s, new ThreadCallbackHandler( this .DownloadFileChunk));
424                         Thread t2 = new Thread( new ThreadStart(x1.StartDownloadFileChunk));
425                          if (threads == null )
426                         {
427                             threads = new ArrayList();
428                         }
429                         threads.Add(t2);
430                         t2.Start();
431                     }
432                 }
433                  // 如果服务器不支持断点续传(Accept-Range), 则使用单线程下载
434                  else
435                 {
436                     AddendInfToControlFile(FileName, 0 , l);
437                     DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, 0 , l, new ThreadCallbackHandler( this .DownloadFileChunk));
438                     Thread t = new Thread( new ThreadStart(x.StartDownloadFileChunk));
439                      if (threads == null )
440                     {
441                         threads = new ArrayList();
442                     }
443                     threads.Add(t);
444                     t.Start();
445                 }
446             }
447              catch (Exception e)
448             {
449                  // if (blnReturn == true)
450                  // {
451                  //     return;
452                  // }
453
454                 ExceptionActions ea = ExceptionActions.Throw;
455                  if (ea == ExceptionActions.Throw)
456                 {
457                      if ( ! (e is WebException) && ! (e is SecurityException))
458                     {
459                          throw new WebException( " net_webclient " , e);
460                     }
461                      throw ;
462                 }
463
464
465                  // if (this.ExceptionOccurrs != null)
466                  // {
467                  //     DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, p, s);
468
469                  //     ExceptionEventArgs eea = new ExceptionEventArgs(e, x);
470                  //     ExceptionOccurrs(this, eea);
471                  //     ea = eea.ExceptionAction;
472                  // }
473
474             }
475
476         }

477
478         #region 操作控制文件(By King Zheng)
479
480         /// <summary>
481         /// 插入文件块信息到控制文件(Add by ChengKing)
482         /// </summary>
483         /// <param name="FileName"></param>
484         /// <param name="Position"></param>
485         /// <param name="Length"></param>
486         private void AddendInfToControlFile(string FileName, int Position, int Length)
487         {
488
489
490             try
491             {
492                 lock (_SyncLockObject)
493                 {
494                     string strControlFile = GetControlFileName(FileName);
495
496
497                     //if (File.Exists(strControlFile) == false)
498                     //{
499                     //    return;
500                     //}
501
502                     using (StreamWriter sw = new StreamWriter(strControlFile, true, Encoding.Default))
503                     {
504                         //sw.NewLine = "$";
505                         sw.WriteLine(Position.ToString() + "," + Length.ToString() + "," + "0");
506                     }
507                     //using (System.IO.FileStream sw = new System.IO.FileStream(strControlFile, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite, System.IO.FileShare.ReadWrite))
508                     //{
509                     //    //sw.Position = e.DownloadState.Position;
510                     //    sw.Write(Position.ToString() + "," + Length.ToString() + "," + "0");
511                     //    sw.Close();
512                     //}
513
514
515
516                 }
517             }
518             catch (Exception e)
519             {
520                 throw new Exception("写控制文件出错!" + e.Message);
521             }
522
523         }
524
525         /// <summary>
526         /// 更新控制文件(Add by ChengKing)
527         /// </summary>
528         /// <param name="FileName"></param>
529         /// <param name="Position"></param>
530         /// <param name="Length"></param>
531         private void UpdateControlFile(string FileName, int Position, int Length)
532         {
533             try
534             {
535                 lock (_SyncLockObject)
536                 {
537                     string strControlFile = GetControlFileName(FileName);
538
539
540                     //if (File.Exists(strControlFile) == false)
541                     //{
542                     //    return;
543                     //}
544
545                     string s = null;
546                     using (StreamReader sr = new System.IO.StreamReader(strControlFile))
547                     {
548                         s = sr.ReadToEnd();
549                         s = s.Replace(Position.ToString() + "," + Length.ToString() + "," + "0", Position.ToString() + "," + Length.ToString() + "," + "1");
550                     }
551                     using (StreamWriter sw = new StreamWriter(strControlFile, false, Encoding.Default))
552                     {
553                         sw.WriteLine(s);
554                     }
555                 }
556             }
557             catch (Exception e)
558             {
559                 throw new Exception("更新控制文件出错!" + e.Message);
560             }
561
562         }
563
564         /// <summary>
565         /// 读取所有信息从控制文件(Add by ChengKing)
566         /// </summary>
567         /// <param name="FileName"></param>
568         /// <returns></returns>
569         private string ReadInfFromControlFile(string FileName)
570         {
571             try
572             {
573                 lock (_SyncLockObject)
574                 {
575                     string strControlFile = GetControlFileName(FileName);
576
577                     string s = null;
578                     using (StreamReader sr = new System.IO.StreamReader(strControlFile))
579                     {
580                         s = sr.ReadToEnd();
581
582                     }
583                     return s;
584                 }
585             }
586             catch (Exception e)
587             {
588                 throw new Exception("读控制文件出错!" + e.Message);
589             }
590         }
591
592         /// <summary>
593         /// 根据目标文件名得到控制文件名(Add by ChengKing)
594         /// </summary>
595         /// <param name="FileName"></param>
596         /// <returns></returns>
597         public string GetControlFileName(string FileName)
598         {
599             string strPath = Path.GetDirectoryName(FileName);
600
601             //string strFileNameWithoutExtension = Path.GetFileNameWithoutExtension(FileName);
602             string strFileNameWithoutExtension = Path.GetFileName(FileName);
603             string strControlFile = Path.Combine(strPath, strFileNameWithoutExtension + "_Control.txt");
604             return strControlFile;
605         }
606
607         /// <summary>
608         /// 判断控制文件是否存在
609         /// </summary>
610         /// <param name="FileName"></param>
611         /// <returns></returns>
612         private bool ExistControlFile(string FileName)
613         {
614             string strControlFile = GetControlFileName(FileName);
615             if (File.Exists(strControlFile))
616             {
617                 return true;
618             }
619             return false;
620         }
621
622         /// <summary>
623         /// 判断控制文件是否完成
624         /// </summary>
625         /// <param name="strControlFile"></param>
626         /// <returns></returns>
627         public bool JudgeControlFileIfFinished(string strControlFile)
628         {
629             try
630             {
631                 string s = null;
632                 lock (_SyncLockObject)
633                 {
634                     using (StreamReader sr = new System.IO.StreamReader(strControlFile))
635                     {
636                         s = sr.ReadToEnd();
637                     }
638                 }
639                 if (s + String.Empty == String.Empty)
640                 {
641                     return false;
642                 }
643                 string[] strBlocks = s.Split(new char[2] { '\r', '\n' });
644                 for (int i = 0; i < strBlocks.Length; i++)
645                 {
646                     if (strBlocks[i].Trim().Length != 0 && strBlocks[i].Substring(strBlocks[i].Length - 1) == "0")
647                     {
648                         return false;
649                     }
650                 }
651                 return true;
652
653             }
654             catch (Exception e)
655             {
656                 throw new Exception("判断控制文件是否完成时, 读取文件出错!" + e.Message);
657             }
658         }
659
660         /// <summary>
661         /// 删除控制文件(Add by ChengKing)
662         /// </summary>
663         /// <param name="strControlFile"></param>
664         /// <returns></returns>
665         public bool DeleteControlFile(string strControlFile)
666         {
667             try
668             {
669                 lock (_SyncLockObject)
670                 {
671                     if (File.Exists(strControlFile))
672                     {
673                         File.Delete(strControlFile);
674                     }
675                 }
676                 return true;
677             }
678             catch (Exception e)
679             {
680                 throw new Exception("删除控制文件出错!" + e.Message);
681             }
682         }
683
684         #endregion
685
686         /// <summary>
687         /// 下载一个文件块,利用该方法可自行实现多线程断点续传
688         /// </summary>
689         /// <param name="Address">URL 地址</param>
690         /// <param name="FileName">保存到本地的路径文件名</param>
691         /// <param name="Length">块大小</param>
692         public void DownloadFileChunk(string Address, string FileName, int FromPosition, int Length)
693         {
694             HttpWebResponse hwrp = null;
695             string a = null;
696             try
697             {
698                 //this._FileName = FileName;
699                 HttpWebRequest hwrq = (HttpWebRequest)WebRequest.Create(this.GetUri(Address));
700                 //hwrq.Credentials = this.m_credentials;
701
702                 hwrq.AddRange(FromPosition);
703
704                 hwrp = (HttpWebResponse)hwrq.GetResponse();
705
706                 //hwrp.Headers.Add("Content-Range", FromPosition.ToString());  //Test
707
708                 a = hwrp.Headers["Content-Disposition"]; //attachment
709                 if (a != null)
710                 {
711                     a = a.Substring(a.LastIndexOf("filename=") + 9);
712                 }
713                 else
714                 {
715                     a = FileName;
716                 }
717
718                 byte[] buffer = this.ResponseAsBytes(Address, hwrp, Length, FileName);
719                 //   lock (_SyncLockObject)
720                 //   {
721                 //    this._Bytes += buffer.Length;
722                 //   }
723             }
724             catch (Exception e)
725             {
726                 ExceptionActions ea = ExceptionActions.Throw;
727                 if (this.ExceptionOccurrs != null)
728                 {
729                     DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, FromPosition, Length);
730                     ExceptionEventArgs eea = new ExceptionEventArgs(e, x);
731                     ExceptionOccurrs(this, eea);
732                     ea = eea.ExceptionAction;
733                 }
734
735                 if (ea == ExceptionActions.Throw)
736                 {
737                     if (!(e is WebException) && !(e is SecurityException))
738                     {
739                         throw new WebException("net_webclient", e);
740                     }
741                     throw;
742                 }
743             }
744         }
745
746         internal byte[] ResponseAsBytes(string RequestURL, WebResponse Response, long Length, string FileName)
747         {
748             string a = null; //AttachmentName
749             int P = 0; //整个文件的位置指针
750             int num2 = 0;
751             int num3 = 0;
752             int intFrom = 0;
753             try
754             {
755                 a = Response.Headers["Content-Disposition"]; //attachment
756                 if (a != null)
757                 {
758                     a = a.Substring(a.LastIndexOf("filename=") + 9);
759                 }
760
761                 long num1 = Length; //Response.ContentLength;
762                 bool flag1 = false;
763                 if (num1 == -1)
764                 {
765                     flag1 = true;
766                     num1 = 0x10000; //64k
767                 }
768                 byte[] buffer1 = new byte[(long)num1];
769
770
771                 int p = 0; //本块的位置指针
772
773                 string s = Response.Headers["Content-Range"];
774                 //string s = hwrq.Headers["Range"];
775
776                 if (s != null)
777                 {
778                     s = s.Replace("bytes ", "");
779                     s = s.Substring(0, s.IndexOf("-"));
780                     P = Convert.ToInt32(s);
781                     intFrom = P;
782
783                 }
784
785                 //int num3 = 0;
786
787                 Stream S = Response.GetResponseStream();
788
789                 int count = 0;
790
791                 int bufferSize = 65535; //允许读取的最大字节
792
793                 int times;
794                 do
795                 {
796                     times = 0;
797
798                     //num2 = S.Read(buffer1, num3, ((int)num1) - num3);
799
800                     //限制最大读取字节
801                     if (bufferSize < ((int)num1) - num3)
802                     {
803                         num2 = S.Read(buffer1, num3, bufferSize);
804                     }
805                     else
806                     {
807                         num2 = S.Read(buffer1, num3, ((int)num1) - num3);
808                     }
809
810                     //网络短时间的不稳定
811                     if (num2 == 0)
812                     {
813                         Thread.Sleep(50);
814                         times++;
815
816                         if (times > 100)
817                         {
818                             throw new Exception("网络传输层错误");
819                         }
820
821                     }
822
823                     num3 += num2;
824                     if (flag1 && (num3 == num1))
825                     {
826                         num1 += 0x10000;
827                         byte[] buffer2 = new byte[(int)num1];
828                         Buffer.BlockCopy(buffer1, 0, buffer2, 0, num3);
829                         buffer1 = buffer2;
830                     }
831
832                     //    lock (_SyncLockObject)
833                     //    {
834                     //     this._bytes += num2;
835                     //    }
836                     if (num2 > 0)
837                     {
838                         if (this.DataReceive != null)
839                         {
840                             byte[] buffer = new byte[num2];
841                             Buffer.BlockCopy(buffer1, p, buffer, 0, buffer.Length);
842                             DownLoadState dls = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, num2, buffer);
843                             DownLoadEventArgs dlea = new DownLoadEventArgs(dls);
844
845                             //触发事件
846                             this.OnDataReceive(dlea);
847                             //System.Threading.Thread.Sleep(100);
848
849                         }
850                         p += num2; //本块的位置指针
851                         P += num2; //整个文件的位置指针
852                     }
853                     else
854                     {
855                         break;
856                     }
857
858                 }
859                 while (num2 != 0);
860
861                 count++;
862
863                 int c = count;
864
865                 S.Close();
866                 S = null;
867                 if (flag1)
868                 {
869                     byte[] buffer3 = new byte[num3];
870                     Buffer.BlockCopy(buffer1, 0, buffer3, 0, num3);
871                     buffer1 = buffer3;
872                 }
873
874                 UpdateControlFile(FileName, intFrom, (int)Length);
875
876                 return buffer1;
877             }
878             catch (Exception e)
879             {
880                 ExceptionActions ea = ExceptionActions.Throw;
881                 if (this.ExceptionOccurrs != null)
882                 {
883                     Thread.Sleep(100);
884                     //DownLoadState x = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, num2);
885                     //DownLoadState x = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, (int)(Length - num3));
886                     DownLoadState x = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, (int)Length);
887
888                     ExceptionEventArgs eea = new ExceptionEventArgs(e, x);
889                     ExceptionOccurrs(this, eea);
890                     ea = eea.ExceptionAction;
891                 }
892
893                 if (ea == ExceptionActions.Throw)
894                 {
895                     if (!(e is WebException) && !(e is SecurityException))
896                     {
897                         throw new WebException("net_webclient", e);
898                     }
899                     throw;
900                 }
901                 return null;
902             }
903         }

904
905         private void OnDataReceive(DownLoadEventArgs e)
906         {
907             //触发数据到达事件
908             DataReceive(this, e);
909         }
910
911         public byte[] UploadFile(string address, string fileName)
912         {
913             return this.UploadFile(address, "POST", fileName, "file");
914         }
915
916         public string UploadFileEx(string address, string method, string fileName, string fieldName)
917         {
918             return Encoding.ASCII.GetString(UploadFile(address, method, fileName, fieldName));
919         }
920
921         public byte[] UploadFile(string address, string method, string fileName, string fieldName)
922         {
923             byte[] buffer4;
924             FileStream stream1 = null;
925             try
926             {
927                 fileName = Path.GetFullPath(fileName);
928                 string text1 = "---------------------" + DateTime.Now.Ticks.ToString("x");
929
930                 string text2 = "application/octet-stream";
931
932                 stream1 = new FileStream(fileName, FileMode.Open, FileAccess.Read);
933                 WebRequest request1 = WebRequest.Create(this.GetUri(address));
934                 request1.Credentials = this.m_credentials;
935                 request1.ContentType = "multipart/form-data; boundary=" + text1;
936
937                 request1.Method = method;
938                 string[] textArray1 = new string[7] { "--", text1, "\r\nContent-Disposition: form-data; name=\"" + fieldName + "\"; filename=\"", Path.GetFileName(fileName), "\"\r\nContent-Type: ", text2, "\r\n\r\n" };
939                 string text3 = string.Concat(textArray1);
940                 byte[] buffer1 = Encoding.UTF8.GetBytes(text3);
941                 byte[] buffer2 = Encoding.ASCII.GetBytes("\r\n--" + text1 + "\r\n");
942                 long num1 = 0x7fffffffffffffff;
943                 try
944                 {
945                     num1 = stream1.Length;
946                     request1.ContentLength = (num1 + buffer1.Length) + buffer2.Length;
947                 }
948                 catch
949                 {
950                 }
951                 byte[] buffer3 = new byte[Math.Min(0x2000, (int)num1)];
952                 using (Stream stream2 = request1.GetRequestStream())
953                 {
954                     int num2;
955                     stream2.Write(buffer1, 0, buffer1.Length);
956                     do
957                     {
958                         num2 = stream1.Read(buffer3, 0, buffer3.Length);
959                         if (num2 != 0)
960                         {
961                             stream2.Write(buffer3, 0, num2);
962                         }
963                     }
964                     while (num2 != 0);
965                     stream2.Write(buffer2, 0, buffer2.Length);
966                 }
967                 stream1.Close();
968                 stream1 = null;
969                 WebResponse response1 = request1.GetResponse();
970
971                 buffer4 = this.ResponseAsBytes(response1);
972             }
973             catch (Exception exception1)
974             {
975                 if (stream1 != null)
976                 {
977                     stream1.Close();
978                     stream1 = null;
979                 }
980                 if (!(exception1 is WebException) && !(exception1 is SecurityException))
981                 {
982                     //throw new WebException(SR.GetString("net_webclient"), exception1);
983                     throw new WebException("net_webclient", exception1);
984                 }
985                 throw;
986             }
987             return buffer4;
988         }
989

990          private byte [] ResponseAsBytes(WebResponse response)
991         {
992              int num2;
993              long num1 = response.ContentLength;
994              bool flag1 = false ;
995              if (num1 == - 1 )
996             {
997                 flag1 = true ;
998                 num1 = 0x10000 ;
999             }
1000              byte [] buffer1 = new byte [( int )num1];
1001             Stream stream1 = response.GetResponseStream();
1002              int num3 = 0 ;
1003              do
1004             {
1005                 num2 = stream1.Read(buffer1, num3, (( int )num1) - num3);
1006                 num3 += num2;
1007                  if (flag1 && (num3 == num1))
1008                 {
1009                     num1 += 0x10000 ;
1010                      byte [] buffer2 = new byte [( int )num1];
1011                     Buffer.BlockCopy(buffer1, 0 , buffer2, 0 , num3);
1012                     buffer1 = buffer2;
1013                 }
1014             }
1015              while (num2 != 0 );
1016             stream1.Close();
1017              if (flag1)
1018             {
1019                  byte [] buffer3 = new byte [num3];
1020                 Buffer.BlockCopy(buffer1, 0 , buffer3, 0 , num3);
1021                 buffer1 = buffer3;
1022             }
1023              return buffer1;
1024         }
1025
1026          private NameValueCollection m_requestParameters;
1027          private Uri m_baseAddress;
1028          private ICredentials m_credentials = CredentialCache.DefaultCredentials;
1029
1030          public ICredentials Credentials
1031         {
1032              get
1033             {
1034                  return this .m_credentials;
1035             }
1036              set
1037             {
1038                  this .m_credentials = value;
1039             }
1040         }
1041
1042          public NameValueCollection QueryString
1043         {
1044              get
1045             {
1046                  if ( this .m_requestParameters == null )
1047                 {
1048                      this .m_requestParameters = new NameValueCollection();
1049                 }
1050                  return this .m_requestParameters;
1051             }
1052              set
1053             {
1054                  this .m_requestParameters = value;
1055             }
1056         }
1057
1058          public string BaseAddress
1059         {
1060              get
1061             {
1062                  if ( this .m_baseAddress != null )
1063                 {
1064                      return this .m_baseAddress.ToString();
1065                 }
1066                  return string .Empty;
1067             }
1068              set
1069             {
1070                  if ((value == null ) || (value.Length == 0 ))
1071                 {
1072                      this .m_baseAddress = null ;
1073                 }
1074                  else
1075                 {
1076                      try
1077                     {
1078                          this .m_baseAddress = new Uri(value);
1079                     }
1080                      catch (Exception exception1)
1081                     {
1082                          throw new ArgumentException( " value " , exception1);
1083                     }
1084                 }
1085             }
1086         }
1087
1088          public Uri GetUri( string path)
1089         {
1090             Uri uri1;
1091              try
1092             {
1093                  if ( this .m_baseAddress != null )
1094                 {
1095                     uri1 = new Uri( this .m_baseAddress, path);
1096                 }
1097                  else
1098                 {
1099                     uri1 = new Uri(path);
1100                 }
1101                  if ( this .m_requestParameters == null )
1102                 {
1103                      return uri1;
1104                 }
1105                 StringBuilder builder1 = new StringBuilder();
1106                  string text1 = string .Empty;
1107                  for ( int num1 = 0 ; num1 < this .m_requestParameters.Count; num1 ++ )
1108                 {
1109                     builder1.Append(text1 + this .m_requestParameters.AllKeys[num1] + " = " + this .m_requestParameters[num1]);
1110                     text1 = " & " ;
1111                 }
1112                 UriBuilder builder2 = new UriBuilder(uri1);
1113                 builder2.Query = builder1.ToString();
1114                 uri1 = builder2.Uri;
1115             }
1116              catch (UriFormatException)
1117             {
1118                 uri1 = new Uri(Path.GetFullPath(path));
1119             }
1120              return uri1;
1121         }
1122
1123     }
1124
1125 }
1126
1127

2.页面 Default.aspx 文件代码

1 < html xmlns = " http://www.w3.org/1999/xhtml " >
2 < head runat = " server " >
3      < script language = " javascript " >
4         mainLoop = function()
5         {
6             var objPath = document.getElementById( " TextBox2 " );
7             var blnValue = _Default.CheckControlFiles(objPath.value);
8              // a.value = a.value + blnValue.value;
9              if ( blnValue.value == true )
10             {
11                 var returnvalue = setTimeout( ' mainLoop() ' , 1000 );
12             }
13              else
14             {
15                 var objStatus = document.getElementById( " Label1 " );
16                 objStatus.innerText = " 状态: 下载完成! " ;
17
18                 var btOK = document.getElementById( " btOK " );
19                 btOK.disabled = "" ;
20
21                 var btCancel = document.getElementById( " btCancel " );
22                 btCancel.disabled = " disabled " ;
23
24             }
25         }
26
27
28      </ script >
29
30 </ head >
31 < body >
32      < form id = " frmTest " runat = " server " >
33      < table bgcolor = " #ffcc66 " >< tr >< td style = " height: 259px " >
34          < br />
35          < strong >< span style = " color: #000099 " >
36         下载组件:
37          < br />
38          1 . 支持多线程: & nbsp;多个线程某时刻下载同一个文件的不同块. < br />
39          2 . 断点续传: & nbsp;如果下载了一个文件的某些块(一半), 则下次 < br />
40              & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 下载时只需下载未完成的块;
41              & nbsp;文件块的下载状 < br />
42              & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 态用控制文件记录.
43             块下载完成的先后顺序不 < br />
44              & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 一定是连续的. < br />
45          </ span ></ strong >
46          < br />
47          < table style = " width: 379px " >
48              < tr >
49                  < td colspan = " 1 " style = " width: 87px " >
50                     Source </ td >
51                  < td colspan = " 2 " style = " width: 326px " >
52          < asp:TextBox ID = " TextBox1 " runat = " server " Width = " 391px " > http: // www.</asp:TextBox></td>
53              </ tr >
54              < tr >
55                  < td colspan = " 1 " style = " width: 87px " >
56                     Location </ td >
57                  < td colspan = " 2 " style = " width: 326px " >
58                      < asp:TextBox ID = " TextBox2 " runat = " server " Width = " 391px " > D:\Documents and Settings\zhengjian\桌面\TestDownLoads\ </ asp:TextBox ></ td >
59              </ tr >
60              < tr >
61                  < td colspan = " 1 " style = " width: 87px " >
62                     Threads </ td >
63                  < td colspan = " 2 " style = " width: 326px " >
64                      < asp:TextBox ID = " TextBox3 " runat = " server " Width = " 390px " > 10 </ asp:TextBox ></ td >
65              </ tr >
66          </ table >
67          < br />
68          < asp:Button ID = " btOK " runat = " server " Text = " 下载 " Height = " 42px " Width = " 108px " OnClick = " btOK_Click " />& nbsp;
69          & nbsp; < asp:Button ID = " btCancel " runat = " server " OnClick = " btCancel_Click " Text = " 取消/暂停 " Height = " 42px " Width = " 108px " Enabled = " False " />< br />
70          < br />
71          < asp:Label ID = " Label1 " runat = " server " Height = " 32px " Text = " 状态: 未开始下载 " Width = " 227px " Font - Bold = " True " ForeColor = " #8080FF " ></ asp:Label >< br />
72          </ td ></ tr ></ table >
73          < script language = javascript >
74             mainLoop();
75          </ script >
76      </ form >
77 </ body >
78 </ html >

3. 页面后台文件 Default.aspx.cs代码

  1 /// <summary>
  2 /// Author: [ ChengKing(ZhengJian) ]
  3 /// Blog:   Http://blog.youkuaiyun.com/ChengKing
  4 /// 注：从网上找了个优秀代码
  5 /// 扩展如下功能:
  6 ///    1. 解决一些线程相关的Bug;
  7 ///    2.扩展用控制文件实现断点续传功能.
  8 /// </summary>
  9 public partial class _Default : System.Web.UI.Page
10 {
11      // 全局变量
12      private static object _SyncLockObject = new object ();
13
14      protected void Page_Load( object sender, EventArgs e)
15     {
16         Utility.RegisterTypeForAjax( typeof (_Default));
17          // this.TextBox1.Text = " http://download.youkuaiyun.com/filedown/aHR0cDovL2Rvd25sb2FkMS5jc2RuLm5ldC9kb3duMy8yMDA3MDUwNy8wNzE4MDIwNzY4OC5yYXI= !177258";
18
19
20          this .TextBox1.Text = " http://files.cnblogs.com/ChengKing/智能象棋游戏(T1).rar " ;
21     }
22      protected void btOK_Click( object sender, EventArgs e)
23     {
24          this .Label1.Text = " 状态: 正在下载

" ;
25
26         DownLoadComponent.HttpWebClient x = new DownLoadComponent.HttpWebClient();
27
28          // 注册 DataReceive　事件
29         x.DataReceive += new DownLoadComponent.HttpWebClient.DataReceiveEventHandler( this .x_DataReceive);
30          // 注册 ExceptionOccurrs　事件
31         x.ExceptionOccurrs += new DownLoadComponent.HttpWebClient.ExceptionEventHandler( this .x_ExceptionOccurrs);
32
33          string Source = this .TextBox1.Text.Trim();
34          string FileName = Source.Substring(Source.LastIndexOf( " / " ) + 1 );
35          string Location = System.IO.Path.Combine( this .TextBox2.Text.Trim() , FileName);
36
37          // F: 源服务器文件;  _f: 保存路径;  10: 自设定一个文件有几个线程下载.
38         x.DownloadFile(Source,Location , int .Parse( this .TextBox3.Text));
39
40          // Response.Write("正在下载文件

");
41          this .btOK.Enabled = false ;
42          this .btCancel.Enabled = true ;
43     }
44
45      private void x_DataReceive(DownLoadComponent.HttpWebClient Sender, DownLoadComponent.DownLoadEventArgs e)
46     {
47
48          string f = e.DownloadState.FileName;
49          if (e.DownloadState.AttachmentName != null )
50             f = System.IO.Path.GetDirectoryName(f) + @" \ " + e.DownloadState.AttachmentName;
51
52          using (System.IO.FileStream sw = new System.IO.FileStream(f, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite, System.IO.FileShare.ReadWrite))
53         {
54             sw.Position = e.DownloadState.Position;
55             sw.Write(e.DownloadState.Data, 0 , e.DownloadState.Data.Length);
56             sw.Close();
57         }
58     }
59
60      private void x_ExceptionOccurrs(DownLoadComponent.HttpWebClient Sender, DownLoadComponent.ExceptionEventArgs e)
61     {
62         System.Console.WriteLine(e.Exception.Message);
63          // 发生异常重新下载相当于断点续传,你可以自己自行选择处理方式或自行处理
64         DownLoadComponent.HttpWebClient x = new DownLoadComponent.HttpWebClient();
65         x.DataReceive += new DownLoadComponent.HttpWebClient.DataReceiveEventHandler( this .x_DataReceive);
66          // 订阅 ExceptionOccurrs　事件
67          // x.ExceptionOccurrs += new DownLoadComponent.HttpWebClient.ExceptionEventHandler(this.x_ExceptionOccurrs);
68
69         x.DownloadFileChunk(e.DownloadState.RequestURL, e.DownloadState.FileName, e.DownloadState.Position, e.DownloadState.Length);
70         e.ExceptionAction = DownLoadComponent.ExceptionActions.Ignore;
71     }
72      protected void btCancel_Click( object sender, EventArgs e)
73     {
74          if (DownLoadComponent.HttpWebClient.threads != null )
75         {
76              foreach (Thread t in DownLoadComponent.HttpWebClient.threads)
77             {
78                  if (t.IsAlive)
79                 {
80                     t.Abort();
81                 }
82             }
83
84             DownLoadComponent.HttpWebClient.threads.Clear();
85         }
86         System.Diagnostics.Process myproc = new System.Diagnostics.Process();
87         Process[] procs = (Process[])Process.GetProcessesByName( " DW20.exe " );   // 得到所有打开的进程
88          try
89         {
90              foreach (Process proc in procs)
91             {
92                  if (proc.CloseMainWindow() == false )
93                 {
94                     proc.Kill();
95                 }
96             }
97         }
98          catch
99         { }
100         KillAllThreads();
101          this .btOK.Enabled = true ;
102          this .btCancel.Enabled = false ;
103         GC.Collect();
104
105     }
106
107      /// <summary>
108      /// 定期检查控制文件
109      /// </summary>
110      /// <param name="str"></param>
111      /// <returns> 是否还继续监视(1: 正在下载中，继续监视; 0: 表示已经下载完毕,不用再检视) </returns>
112     [AjaxMethod()] // or [AjaxPro.AjaxMethod]
113      public bool CheckControlFiles( string strObjPath)
114     {
115          if ( ! WhetherDownloadFinished(strObjPath))
116         {
117              return true ;
118         }
119          return false ;
120     }
121
122      private bool WhetherDownloadFinished( string strObjPath)
123     {
124         DirectoryInfo df = new DirectoryInfo(strObjPath);
125         FileInfo[] fi = (FileInfo[])df.GetFiles( " *.txt " , SearchOption.TopDirectoryOnly);
126         HttpWebClient hwc = new HttpWebClient();
127          for ( int i = 0 ; i < fi.Length; i ++ )
128         {
129              if (fi[i].FullName.Length > 12 && fi[i].FullName.Substring(fi[i].FullName.Length - 12 ) == " _Control.txt " )
130             {
131                  if (hwc.JudgeControlFileIfFinished(fi[i].FullName) == true )
132                 {
133                     hwc.DeleteControlFile(fi[i].FullName);
134                     KillAllThreads();
135                      return true ;
136                 }
137             }
138         }
139          return false ;
140     }
141
142      private void KillAllThreads()
143     {
144          foreach (Thread t in HttpWebClient.threads)
145         {
146              if (t.IsAlive)
147             {
148                 t.Abort();
149             }
150         }
151         HttpWebClient.threads.Clear();
152     }
153
154 }
155

(四).示例代码下载

http://files.cnblogs.com/MVP33650/MultiThreadDownLoadFile.rar

(五).Asp.net 2.0其它相关文章:

http://blog.youkuaiyun.com/ChengKing/category/288694.aspx

转载于:https://www.cnblogs.com/hdjjun/archive/2008/06/17/1223891.html