1 public class Program
2 {
3 public static CountdownEvent cde = new CountdownEvent(0);
4
5 //每个线程下载的字节数，方便最后合并
6 public static ConcurrentDictionary<long, byte[]> dic = new ConcurrentDictionary<long, byte[]>();
7
8 //请求文件
9 public static string url = "http://www.pncity.net/bbs/data/attachment/forum/201107/30/1901108yyd8gnrs2isadrr.jpg";
10
11 static void Main(string[] args)
12 {
13 for (int i = 0; i < 5; i++)
14 {
15 Console.WriteLine("\n****************************\n第{0}次比较\n****************************", (i + 1));
16
17 //不用线程
18 //RunSingle();
19
20 //使用多线程
21 RunMultiTask();
22 }
23
24 Console.Read();
25 }
26
27 static void RunMultiTask()
28 {
29 Stopwatch watch = Stopwatch.StartNew();
30
31 //开5个线程
32 int threadCount = 5;
33
34 long start = 0;
35
36 long end = 0;
37
38 var total = GetSourceHead();
39
40 if (total == 0)
41 return;
42
43 var pageSize = (int)Math.Ceiling((Double)total / threadCount);
44
45 // cde.Reset(threadCount);
46
47 Task[] tasks = new Task[threadCount];
48
49 for (int i = 0; i < threadCount; i++)
50 {
51 start = i * pageSize;
52
53 end = (i + 1) * pageSize - 1;
54
55 if (end > total)
56 end = total;
57
58 var obj = start + "|" + end;
59
60 tasks[i] = Task.Factory.StartNew(j => new DownFile().DownTaskMulti(obj), obj);
61 }
62
63 Task.WaitAll(tasks);
64
65 var targetFile = "C://down//" + url.Substring(url.LastIndexOf('/') + 1);
66
67 FileStream fs = new FileStream(targetFile, FileMode.Create);
68
69 var result = dic.Keys.OrderBy(i => i).ToList();
70
71 foreach (var item in result)
72 {
73 fs.Write(dic[item], 0, dic[item].Length);
74 }
75
76 fs.Close();
77
78 watch.Stop();
79
80 Console.WriteLine("多线程：下载耗费时间:{0}", watch.Elapsed);
81 }
82
83 static void RunSingle()
84 {
85 Stopwatch watch = Stopwatch.StartNew();
86
87 if (GetSourceHead() == 0)
88 return;
89
90 var request = (HttpWebRequest)HttpWebRequest.Create(url);
91
92 var response = (HttpWebResponse)request.GetResponse();
93
94 var stream = response.GetResponseStream();
95
96 var outStream = new MemoryStream();
97
98 var bytes = new byte[10240];
99
100 int count = 0;
101
102 while ((count = stream.Read(bytes, 0, bytes.Length)) != 0)
103 {
104 outStream.Write(bytes, 0, count);
105 }
106
107 var targetFile = "C://down//" + url.Substring(url.LastIndexOf('/') + 1);
108
109 FileStream fs = new FileStream(targetFile, FileMode.Create);
110
111 fs.Write(outStream.ToArray(), 0, (int)outStream.Length);
112
113 outStream.Close();
114
115 response.Close();
116
117 fs.Close();
118
119 watch.Stop();
120
121 Console.WriteLine("不用线程：下载耗费时间:{0}", watch.Elapsed);
122 }
123
124 //获取头信息
125 public static long GetSourceHead()
126 {
127 var request = (HttpWebRequest)HttpWebRequest.Create(url);
128
129 request.Method = "Head";
130 request.Timeout = 3000;
131
132 var response = (HttpWebResponse)request.GetResponse();
133
134 var code = response.StatusCode;
135
136 if (code != HttpStatusCode.OK)
137 {
138 Console.WriteLine("下载的资源无效！");
139 return 0;
140 }
141
142 var total = response.ContentLength;
143
144 Console.WriteLine("当前资源大小为:" + total);
145
146 response.Close();
147
148 return total;
149 }
150 }
151
152 public class DownFile
153 {
154 // 多线程下载
155 public void DownTaskMulti(object obj)
156 {
157 var single = obj.ToString().Split('|');
158
159 long start = Convert.ToInt64(single.FirstOrDefault());
160
161 long end = Convert.ToInt64(single.LastOrDefault());
162
163 var request = (HttpWebRequest)HttpWebRequest.Create(Program.url);
164
165 request.AddRange(start, end);
166
167 var response = (HttpWebResponse)request.GetResponse();
168
169 var stream = response.GetResponseStream();
170
171 var outStream = new MemoryStream();
172
173 var bytes = new byte[10240];
174
175 int count = 0;
176
177 while ((count = stream.Read(bytes, 0, bytes.Length)) != 0)
178 {
179 outStream.Write(bytes, 0, count);
180 }
181
182 outStream.Close();
183
184 response.Close();
185
186 Program.dic.TryAdd(start, outStream.ToArray());
187
188 // Program.cde.Signal();
189 }
190 }
