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)

(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.net2.0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(AddbyChengKing)
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,ThreadCallbackHandlertch)
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 DownLoadStateDownloadState
203 {
204 get
205 {
206 return _DownloadState;
207 }
208 }
209
210 public ExceptionException
211 {
212 get
213 {
214 return _Exception;
215 }
216 }
217
218 public ExceptionActionsExceptionAction
219 {
220 get
221 {
222 return _ExceptionAction;
223 }
224 set
225 {
226 _ExceptionAction = value;
227 }
228 }
229
230 internal ExceptionEventArgs(System.Exceptione,DownLoadStateDownloadState)
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 DownLoadStateDownloadState
245 {
246 get
247 {
248 return _DownloadState;
249 }
250 }
251
252 public DownLoadEventArgs(DownLoadStateDownloadState)
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(HttpWebClientSender,DownLoadEventArgse);
267
268 public event DataReceiveEventHandlerDataReceive; // 接收字节数据事件
269
270 public delegate void ExceptionEventHandler(HttpWebClientSender,ExceptionEventArgse);
271
272 public event ExceptionEventHandlerExceptionOccurrs; // 发生异常事件
273
274 private int _FileLength; // 下载文件的总大小
275
276 public static ArrayListthreads;
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 /// <paramname="Address"> URL地址 </param>
290 /// <paramname="FileName"> 保存到本地的路径文件名 </param>
291 /// <paramname="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 ; // chunksize
296 string a = null ;
297 HttpWebRequesthwrq;
298 HttpWebResponsehwrp = 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 // WebProxywp=WebProxy.GetDefaultProxy();
308 // hwrq.Proxy=wp;
309 hwrq.Method = " GET " ;
310 try
311 {
312 hwrp = (HttpWebResponse)hwrq.GetResponse();
313 }
314 catch (Exceptione)
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 []strRe