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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.csdn.net/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
