实现支持断点续传多线程下载的 Http Web 客户端工具类代码,CSharp代码库,德仔网

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【CSharp】实现支持断点续传多线程下载的 Http Web 客户端工具类
作者:Dezai.CN / 发布于2012/3/20/ 545
实现支持断点续传多线程下载的 Http Web 客户端工具类
<div><font face="Courier New">* .Net/C#: 实现支持断点续传多线程下载的 Http Web 客户端工具类 (C# DIY HttpWebClient) 
* <span style="color: rgb(255, 0, 0);">Reflector</span> 了一下 <span style="color: rgb(255, 0, 0);">System.Net.WebClient</span> ,<span style="color: rgb(255, 0, 0);">改写</span><span style="color: rgb(0, 0, 255);">或增加</span>了若干: 
* <span style="color: rgb(255, 0, 0);">DownLoad、Upload</span> 相关方法! 
* </font><span style="font-family: "Courier New";"><span style="color: rgb(0, 0, 255);">DownLoad 相关改动较大! 
</span> * 增加了 <span style="color: rgb(255, 0, 0);">DataReceive、ExceptionOccurrs </span>事件! 
* 了解服务器端与客户端交互的 HTTP 协议参阅: 
* </span><a href="http://blog.csdn.net/playyuer/archive/2004/08/02/58281.aspx" target="_blank"><span style="color: rgb(0, 0, 128); font-family: "Courier New";">使文件下载的自定义连接支持 FlashGet 的断点续传多线程链接下载! JSP/Servlet 实现!</span></a> 
<span style="font-family: "Courier New";"> * </span><a href="http://blog.csdn.net/playyuer/archive/2004/08/02/58430.aspx" target="_blank"><span style="color: rgb(0, 0, 255); font-family: "Courier New";">http://blog.csdn.net/playyuer/archive/2004/08/02/58430.aspx</span></a> 
<span style="font-family: "Courier New";"> * </span><a href="http://blog.csdn.net/playyuer/archive/2004/08/02/58430.aspx" target="_blank"><span style="color: rgb(0, 0, 128); font-family: "Courier New";">使文件下载的自定义连接支持 FlashGet 的断点续传多线程链接下载! C#/ASP.Net 实现! </span></a> 
<span style="font-family: "Courier New";"> * </span><a href="http://blog.csdn.net/playyuer/archive/2004/08/02/58281.aspx" target="_blank"><span style="color: rgb(0, 0, 255); font-family: "Courier New";">http://blog.csdn.net/playyuer/archive/2004/08/02/58281.aspx</span></a> 
<span style="font-family: "Courier New";"> */ 

</span><span style="font-family: "Courier New";">
<span style="font-family: "Courier New";">2005-03-14 修订:</span>
/* .Net/C#: 实现支持断点续传多线程下载的工具类 
* Reflector 了一下 System.Net.WebClient ,改写或增加了若干: 
* DownLoad、Upload 相关方法! 
* 增加了 DataReceive、ExceptionOccurrs　事件 
*/
namespace Microshaoft.Utils 
{ 
using System; 
using System.IO; 
using System.Net; 
using System.Text; 
using System.Security; 
using System.Threading; 
using System.Collections.Specialized;
/// <summary> 
/// 记录下载的字节位置 
/// </summary> 
public class DownLoadState 
{ 
private string _FileName;
private string _AttachmentName; 
private int _Position; 
private string _RequestURL; 
private string _ResponseURL; 
private int _Length;
private byte[] _Data;
public string FileName 
{ 
get 
{ 
return _FileName; 
} 
}
public int Position 
{ 
get 
{ 
return _Position; 
} 
}
public int Length 
{ 
get 
{ 
return _Length; 
} 
}

public string AttachmentName 
{ 
get 
{ 
return _AttachmentName; 
} 
}
public string RequestURL 
{ 
get 
{ 
return _RequestURL; 
} 
}
public string ResponseURL 
{ 
get 
{ 
return _ResponseURL; 
} 
}

public byte[] Data 
{ 
get 
{ 
return _Data; 
} 
}
internal DownLoadState(string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length, byte[] Data) 
{ 
this._FileName = FileName; 
this._RequestURL = RequestURL; 
this._ResponseURL = ResponseURL; 
this._AttachmentName = AttachmentName; 
this._Position = Position; 
this._Data = Data; 
this._Length = Length; 
}
internal DownLoadState(string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length, ThreadCallbackHandler tch) 
{ 
this._RequestURL = RequestURL; 
this._ResponseURL = ResponseURL; 
this._FileName = FileName; 
this._AttachmentName = AttachmentName; 
this._Position = Position; 
this._Length = Length; 
this._ThreadCallback = tch; 
}
internal DownLoadState(string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length) 
{ 
this._RequestURL = RequestURL; 
this._ResponseURL = ResponseURL; 
this._FileName = FileName; 
this._AttachmentName = AttachmentName; 
this._Position = Position; 
this._Length = Length; 
}
private ThreadCallbackHandler _ThreadCallback;
public HttpWebClient httpWebClient 
{ 
get 
{ 
return this._hwc; 
} 
set 
{ 
this._hwc = value; 
} 
}
internal Thread thread 
{ 
get 
{ 
return _thread; 
} 
set 
{ 
_thread = value; 
} 
}
private HttpWebClient _hwc; 
private Thread _thread;
// 
internal void StartDownloadFileChunk() 
{ 
if (this._ThreadCallback != null) 
{ 
this._ThreadCallback(this._RequestURL, this._FileName, this._Position, this._Length); 
this._hwc.OnThreadProcess(this._thread); 
} 
}
}
//委托代理线程的所执行的方法签名一致 
public delegate void ThreadCallbackHandler(string S, string s, int I, int i);
//异常处理动作 
public enum ExceptionActions 
{ 
Throw, 
CancelAll, 
Ignore, 
Retry 
}
/// <summary> 
/// 包含 Exception 事件数据的类 
/// </summary> 
public class ExceptionEventArgs : System.EventArgs 
{ 
private System.Exception _Exception; 
private ExceptionActions _ExceptionAction;
private DownLoadState _DownloadState;
public DownLoadState DownloadState 
{ 
get 
{ 
return _DownloadState; 
} 
}
public Exception Exception 
{ 
get 
{ 
return _Exception; 
} 
}
public ExceptionActions ExceptionAction 
{ 
get 
{ 
return _ExceptionAction; 
} 
set 
{ 
_ExceptionAction = value; 
} 
}
internal ExceptionEventArgs(System.Exception e, DownLoadState DownloadState) 
{ 
this._Exception = e; 
this._DownloadState = DownloadState; 
} 
}
/// <summary> 
/// 包含 DownLoad 事件数据的类 
/// </summary> 
public class DownLoadEventArgs : System.EventArgs 
{ 
private DownLoadState _DownloadState;
public DownLoadState DownloadState 
{ 
get 
{ 
return _DownloadState; 
} 
}
public DownLoadEventArgs(DownLoadState DownloadState) 
{ 
this._DownloadState = DownloadState; 
}
}
public class ThreadProcessEventArgs : System.EventArgs 
{ 
private Thread _thread;
public Thread thread 
{ 
get 
{ 
return this._thread; 
} 
}
public ThreadProcessEventArgs(Thread thread) 
{ 
this._thread = thread; 
}
}
/// <summary> 
/// 支持断点续传多线程下载的类 
/// </summary> 
public class HttpWebClient 
{ 
private static object _SyncLockObject = new object();
public delegate void DataReceiveEventHandler(HttpWebClient Sender, DownLoadEventArgs e);
public event DataReceiveEventHandler DataReceive; //接收字节数据事件
public delegate void ExceptionEventHandler(HttpWebClient Sender, ExceptionEventArgs e);
public event ExceptionEventHandler ExceptionOccurrs; //发生异常事件
public delegate void ThreadProcessEventHandler(HttpWebClient Sender, ThreadProcessEventArgs e);
public event ThreadProcessEventHandler ThreadProcessEnd; //发生多线程处理完毕事件

private int _FileLength; //下载文件的总大小
public int FileLength 
{ 
get 
{ 
return _FileLength; 
} 
}
/// <summary> 
/// 分块下载文件 
/// </summary> 
/// <param name="Address">URL 地址</param> 
/// <param name="FileName">保存到本地的路径文件名</param> 
/// <param name="ChunksCount">块数,线程数</param> 
public void DownloadFile(string Address, string FileName, int ChunksCount) 
{ 
int p = 0; // position 
int s = 0; // chunk size 
string a = null; 
HttpWebRequest hwrq; 
HttpWebResponse hwrp = null; 
try 
{ 
hwrq = (HttpWebRequest) WebRequest.Create(this.GetUri(Address)); 
hwrp = (HttpWebResponse) hwrq.GetResponse(); 
long L = hwrp.ContentLength;
hwrq.Credentials = this.m_credentials;
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
int l = (int) L;
this._FileLength = l;
//    在本地预定空间(竟然在多线程下不用先预定空间) 
//    FileStream sw = new FileStream(FileName, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite); 
//    sw.Write(new byte[l], 0, l); 
//    sw.Close(); 
//    sw = null;
bool b = (hwrp.Headers["Accept-Ranges"] != null & hwrp.Headers["Accept-Ranges"] == "bytes"); 
a = hwrp.Headers["Content-Disposition"]; //attachment 
if (a != null) 
{ 
a = a.Substring(a.LastIndexOf("filename=") + 9); 
} 
else 
{ 
a = FileName; 
}
int ss = s; 
if (b) 
{ 
s = l / ChunksCount; 
if (s < 2 * 64 * 1024) //块大小至少为 128 K 字节 
{ 
s = 2 * 64 * 1024; 
} 
ss = s; 
int i = 0; 
while (l > s) 
{ 
l -= s; 
if (l < s) 
{ 
s += l; 
} 
if (i++ > 0) 
{ 
DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, p, s, new ThreadCallbackHandler(this.DownloadFileChunk)); 
//       单线程下载 
//       x.StartDownloadFileChunk();
x.httpWebClient = this; 
//多线程下载 
Thread t = new Thread(new ThreadStart(x.StartDownloadFileChunk)); 
//this.OnThreadProcess(t); 
t.Start();
} 
p += s; 
} 
s = ss; 
byte[] buffer = this.ResponseAsBytes(Address, hwrp, s, FileName); 
this.OnThreadProcess(Thread.CurrentThread);
//    lock (_SyncLockObject) 
//    { 
//     this._Bytes += buffer.Length; 
//    } 
} 
} 
catch (Exception e) 
{ 
ExceptionActions ea = ExceptionActions.Throw; 
if (this.ExceptionOccurrs != null) 
{ 
DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, p, s); 
ExceptionEventArgs eea = new ExceptionEventArgs(e, x); 
ExceptionOccurrs(this, eea); 
ea = eea.ExceptionAction; 
}
if (ea == ExceptionActions.Throw) 
{ 
if (!(e is WebException) && !(e is SecurityException)) 
{ 
throw new WebException("net_webclient", e); 
} 
throw; 
} 
}
}
internal void OnThreadProcess(Thread t) 
{ 
if (ThreadProcessEnd != null) 
{ 
ThreadProcessEventArgs tpea = new ThreadProcessEventArgs(t); 
ThreadProcessEnd(this, tpea); 
} 
}
/// <summary> 
/// 下载一个文件块,利用该方法可自行实现多线程断点续传 
/// </summary> 
/// <param name="Address">URL 地址</param> 
/// <param name="FileName">保存到本地的路径文件名</param> 
/// <param name="Length">块大小</param> 
public void DownloadFileChunk(string Address, string FileName, int FromPosition, int Length) 
{ 
HttpWebResponse hwrp = null; 
string a = null; 
try 
{ 
//this._FileName = FileName; 
HttpWebRequest hwrq = (HttpWebRequest) WebRequest.Create(this.GetUri(Address)); 
//hwrq.Credentials = this.m_credentials; 
hwrq.AddRange(FromPosition); 
hwrp = (HttpWebResponse) hwrq.GetResponse(); 
a = hwrp.Headers["Content-Disposition"]; //attachment 
if (a != null) 
{ 
a = a.Substring(a.LastIndexOf("filename=") + 9); 
} 
else 
{ 
a = FileName; 
}
byte[] buffer = this.ResponseAsBytes(Address, hwrp, Length, FileName); 
//   lock (_SyncLockObject) 
//   { 
//    this._Bytes += buffer.Length; 
//   } 
} 
catch (Exception e) 
{ 
ExceptionActions ea = ExceptionActions.Throw; 
if (this.ExceptionOccurrs != null) 
{ 
DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, FromPosition, Length); 
ExceptionEventArgs eea = new ExceptionEventArgs(e, x); 
ExceptionOccurrs(this, eea); 
ea = eea.ExceptionAction; 
}
if (ea == ExceptionActions.Throw) 
{ 
if (!(e is WebException) && !(e is SecurityException)) 
{ 
throw new WebException("net_webclient", e); 
} 
throw; 
} 
} 
}
internal byte[] ResponseAsBytes(string RequestURL, WebResponse Response, long Length, string FileName) 
{ 
string a = null; //AttachmentName 
int P = 0; //整个文件的位置指针 
int num2 = 0; 
try 
{ 
a = Response.Headers["Content-Disposition"]; //attachment 
if (a != null) 
{ 
a = a.Substring(a.LastIndexOf("filename=") + 9); 
}
long num1 = Length; //Response.ContentLength; 
bool flag1 = false; 
if (num1 == -1) 
{ 
flag1 = true; 
num1 = 0x10000; //64k 
} 
byte[] buffer1 = new byte[(int) num1];

int p = 0; //本块的位置指针
string s = Response.Headers["Content-Range"]; 
if (s != null) 
{ 
s = s.Replace("bytes ", ""); 
s = s.Substring(0, s.IndexOf("-")); 
P = Convert.ToInt32(s); 
} 
int num3 = 0;
Stream S = Response.GetResponseStream(); 
do 
{ 
num2 = S.Read(buffer1, num3, ((int) num1) - num3);
num3 += num2; 
if (flag1 && (num3 == num1)) 
{ 
num1 += 0x10000; 
byte[] buffer2 = new byte[(int) num1]; 
Buffer.BlockCopy(buffer1, 0, buffer2, 0, num3); 
buffer1 = buffer2; 
}
//    lock (_SyncLockObject) 
//    { 
//     this._bytes += num2; 
//    } 
if (num2 > 0) 
{ 
if (this.DataReceive != null) 
{ 
byte[] buffer = new byte[num2]; 
Buffer.BlockCopy(buffer1, p, buffer, 0, buffer.Length); 
DownLoadState dls = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, num2, buffer); 
DownLoadEventArgs dlea = new DownLoadEventArgs(dls); 
//触发事件 
this.OnDataReceive(dlea); 
//System.Threading.Thread.Sleep(100);
} 
p += num2; //本块的位置指针 
P += num2; //整个文件的位置指针 
} 
else 
{ 
break; 
}
} 
while (num2 != 0);
S.Close(); 
S = null; 
if (flag1) 
{ 
byte[] buffer3 = new byte[num3]; 
Buffer.BlockCopy(buffer1, 0, buffer3, 0, num3); 
buffer1 = buffer3; 
} 
return buffer1; 
} 
catch (Exception e) 
{ 
ExceptionActions ea = ExceptionActions.Throw; 
if (this.ExceptionOccurrs != null) 
{ 
DownLoadState x = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, num2); 
ExceptionEventArgs eea = new ExceptionEventArgs(e, x); 
ExceptionOccurrs(this, eea); 
ea = eea.ExceptionAction; 
}
if (ea == ExceptionActions.Throw) 
{ 
if (!(e is WebException) && !(e is SecurityException)) 
{ 
throw new WebException("net_webclient", e); 
} 
throw; 
} 
return null; 
} 
}
private void OnDataReceive(DownLoadEventArgs e) 
{ 
//触发数据到达事件 
DataReceive(this, e); 
}
public byte[] UploadFile(string address, string fileName) 
{ 
return this.UploadFile(address, "POST", fileName, "file"); 
}
public string UploadFileEx(string address, string method, string fileName, string fieldName) 
{ 
return Encoding.ASCII.GetString(UploadFile(address, method, fileName, fieldName)); 
}
public byte[] UploadFile(string address, string method, string fileName, string fieldName) 
{ 
byte[] buffer4; 
FileStream stream1 = null; 
try 
{ 
fileName = Path.GetFullPath(fileName); 
string text1 = "---------------------" + DateTime.Now.Ticks.ToString("x");
string text2 = "application/octet-stream";
stream1 = new FileStream(fileName, FileMode.Open, FileAccess.Read); 
WebRequest request1 = WebRequest.Create(this.GetUri(address)); 
request1.Credentials = this.m_credentials; 
request1.ContentType = "multipart/form-data; boundary=" + text1;
request1.Method = method; 
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"}; 
string text3 = string.Concat(textArray1); 
byte[] buffer1 = Encoding.UTF8.GetBytes(text3); 
byte[] buffer2 = Encoding.ASCII.GetBytes("/r/n--" + text1 + "/r/n"); 
long num1 = 0x7fffffffffffffff; 
try 
{ 
num1 = stream1.Length; 
request1.ContentLength = (num1 + buffer1.Length) + buffer2.Length; 
} 
catch 
{ 
} 
byte[] buffer3 = new byte[Math.Min(0x2000, (int) num1)]; 
using (Stream stream2 = request1.GetRequestStream()) 
{ 
int num2; 
stream2.Write(buffer1, 0, buffer1.Length); 
do 
{ 
num2 = stream1.Read(buffer3, 0, buffer3.Length); 
if (num2 != 0) 
{ 
stream2.Write(buffer3, 0, num2); 
} 
} 
while (num2 != 0); 
stream2.Write(buffer2, 0, buffer2.Length); 
} 
stream1.Close(); 
stream1 = null; 
WebResponse response1 = request1.GetResponse();
buffer4 = this.ResponseAsBytes(response1); 
} 
catch (Exception exception1) 
{ 
if (stream1 != null) 
{ 
stream1.Close(); 
stream1 = null; 
} 
if (!(exception1 is WebException) && !(exception1 is SecurityException)) 
{ 
//throw new WebException(SR.GetString("net_webclient"), exception1); 
throw new WebException("net_webclient", exception1); 
} 
throw; 
} 
return buffer4; 
}
private byte[] ResponseAsBytes(WebResponse response) 
{ 
int num2; 
long num1 = response.ContentLength; 
bool flag1 = false; 
if (num1 == -1) 
{ 
flag1 = true; 
num1 = 0x10000; 
} 
byte[] buffer1 = new byte[(int) num1]; 
Stream stream1 = response.GetResponseStream(); 
int num3 = 0; 
do 
{ 
num2 = stream1.Read(buffer1, num3, ((int) num1) - num3); 
num3 += num2; 
if (flag1 && (num3 == num1)) 
{ 
num1 += 0x10000; 
byte[] buffer2 = new byte[(int) num1]; 
Buffer.BlockCopy(buffer1, 0, buffer2, 0, num3); 
buffer1 = buffer2; 
} 
} 
while (num2 != 0); 
stream1.Close(); 
if (flag1) 
{ 
byte[] buffer3 = new byte[num3]; 
Buffer.BlockCopy(buffer1, 0, buffer3, 0, num3); 
buffer1 = buffer3; 
} 
return buffer1; 
}
private NameValueCollection m_requestParameters; 
private Uri m_baseAddress; 
private ICredentials m_credentials = CredentialCache.DefaultCredentials;
public ICredentials Credentials 
{ 
get 
{ 
return this.m_credentials; 
} 
set 
{ 
this.m_credentials = value; 
} 
}
public NameValueCollection QueryString 
{ 
get 
{ 
if (this.m_requestParameters == null) 
{ 
this.m_requestParameters = new NameValueCollection(); 
} 
return this.m_requestParameters; 
} 
set 
{ 
this.m_requestParameters = value; 
} 
}
public string BaseAddress 
{ 
get 
{ 
if (this.m_baseAddress != null) 
{ 
return this.m_baseAddress.ToString(); 
} 
return string.Empty; 
} 
set 
{ 
if ((value == null) || (value.Length == 0)) 
{ 
this.m_baseAddress = null; 
} 
else 
{ 
try 
{ 
this.m_baseAddress = new Uri(value); 
} 
catch (Exception exception1) 
{ 
throw new ArgumentException("value", exception1); 
} 
} 
} 
}
private Uri GetUri(string path) 
{ 
Uri uri1; 
try 
{ 
if (this.m_baseAddress != null) 
{ 
uri1 = new Uri(this.m_baseAddress, path); 
} 
else 
{ 
uri1 = new Uri(path); 
} 
if (this.m_requestParameters == null) 
{ 
return uri1; 
} 
StringBuilder builder1 = new StringBuilder(); 
string text1 = string.Empty; 
for (int num1 = 0; num1 < this.m_requestParameters.Count; num1++) 
{ 
builder1.Append(text1 + this.m_requestParameters.AllKeys[num1] + "=" + this.m_requestParameters[num1]); 
text1 = "&"; 
} 
UriBuilder builder2 = new UriBuilder(uri1); 
builder2.Query = builder1.ToString(); 
uri1 = builder2.Uri; 
} 
catch (UriFormatException) 
{ 
uri1 = new Uri(Path.GetFullPath(path)); 
} 
return uri1; 
}
}
}
/// <summary> 
/// 测试类 
/// </summary> 
class AppTest 
{ 
int _k = 0; 
int _K = 0;
static void Main() 
{ 
AppTest a = new AppTest(); 
Microshaoft.Utils.HttpWebClient x = new Microshaoft.Utils.HttpWebClient();

a._K = 10;
//订阅 DataReceive　事件 
x.DataReceive += new Microshaoft.Utils.HttpWebClient.DataReceiveEventHandler(a.x_DataReceive); 
//订阅 ExceptionOccurrs　事件 
x.ExceptionOccurrs += new Microshaoft.Utils.HttpWebClient.ExceptionEventHandler(a.x_ExceptionOccurrs);
x.ThreadProcessEnd += new Microshaoft.Utils.HttpWebClient.ThreadProcessEventHandler(a.x_ThreadProcessEnd); 
string F = "http://localhost/download/phpMyAdmin-2.6.1-pl2.zip"; 
a._F = F; 
F = "http://localhost/download/jdk-1_5_0_01-windows-i586-p.aa.exe";
string f = F.Substring(F.LastIndexOf("/") + 1);
//(new System.Threading.Thread(new System.Threading.ThreadStart(new ThreadProcessState(F, @"E:/temp/" + f, 10, x).StartThreadProcess))).Start();
x.DownloadFile(F, @"E:/temp/temp/" + f, a._K); 
//  x.DownloadFileChunk(F, @"E:/temp/" + f,15,34556);
System.Console.ReadLine(); 
//  string uploadfile = "e://test_local.rar"; 
//  string str = x.UploadFileEx("http://localhost/phpmyadmin/uploadaction.php", "POST", uploadfile, "file1"); 
//  System.Console.WriteLine(str); 
//  System.Console.ReadLine(); 
}
string bs = ""; //用于记录上次的位数 
bool b = false; 
private int i = 0; 
private static object _SyncLockObject = new object(); 
string _F; 
string _f;
private void x_DataReceive(Microshaoft.Utils.HttpWebClient Sender, Microshaoft.Utils.DownLoadEventArgs e) 
{ 
if (!this.b) 
{ 
lock (_SyncLockObject) 
{ 
if (!this.b) 
{ 
System.Console.Write(System.DateTime.Now.ToString() + " 已接收数据:           "); 
//System.Console.Write( System.DateTime.Now.ToString() + " 已接收数据:           "); 
this.b = true; 
} 
} 
} 
string f = e.DownloadState.FileName; 
if (e.DownloadState.AttachmentName != null) 
f = System.IO.Path.GetDirectoryName(f) + @"/" + e.DownloadState.AttachmentName;
this._f = f;
using (System.IO.FileStream sw = new System.IO.FileStream(f, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite, System.IO.FileShare.ReadWrite)) 
{ 
sw.Position = e.DownloadState.Position; 
sw.Write(e.DownloadState.Data, 0, e.DownloadState.Data.Length); 
sw.Close(); 
} 
string s = System.DateTime.Now.ToString(); 
lock (_SyncLockObject) 
{ 
this.i += e.DownloadState.Data.Length; 
System.Console.Write(bs + "/b/b/b/b/b/b/b/b/b/b" + i + " / " + Sender.FileLength + " 字节数据 " + s); 
//System.Console.Write(bs + i + " 字节数据 " + s); 
this.bs = new string('/b', Digits(i) + 3 + Digits(Sender.FileLength) + s.Length); 
} 
}
int Digits(int n) //数字所占位数 
{ 
n = System.Math.Abs(n); 
n = n / 10; 
int i = 1; 
while (n > 0) 
{ 
n = n / 10; 
i++; 
} 
return i; 
}
private void x_ExceptionOccurrs(Microshaoft.Utils.HttpWebClient Sender, Microshaoft.Utils.ExceptionEventArgs e) 
{ 
System.Console.WriteLine(e.Exception.Message); 
//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 
Microshaoft.Utils.HttpWebClient x = new Microshaoft.Utils.HttpWebClient(); 
x.DownloadFileChunk(this._F, this._f, e.DownloadState.Position, e.DownloadState.Length); 
e.ExceptionAction = Microshaoft.Utils.ExceptionActions.Ignore; 
}
private void x_ThreadProcessEnd(Microshaoft.Utils.HttpWebClient Sender, Microshaoft.Utils.ThreadProcessEventArgs e) 
{ 
//if (e.thread.ThreadState == System.Threading.ThreadState.Stopped) 
if (this._k ++ == this._K - 1) 
System.Console.WriteLine("/nend"); 
} 
}
</span></div>
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　断点续传多线程下载　
同语言下
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