请问以下代码(可以进行断点多传输的主要代码)
断点传输我已经看懂了,主要是用AddRange的方法.可是多线程却有点看不懂.
例如我十个线程分块下载,可能我每一块都在下.突然断电了.然后我再用十个线程去下载.现在的问题是这代码是怎么样保证这十个线程所下载下来的代码是怎么样组合在一起的呢?
实现原更是怎么样的呢?请高人指点.
(注:此代码是由网上一位高人提供的,不是我写的,如果能得到他的指点就更好了)谢谢大家.
/// <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(); //多线程下载
//Thread t =
new Thread(new ThreadStart(x.StartDownloadFileChunk)).Start();
//t.Start();
}
p += s;
}
s = ss;
byte[] buffer = this.ResponseAsBytes(Address, hwrp, s, 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, 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;
}
} } /// <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;
}
}
断点传输我已经看懂了,主要是用AddRange的方法.可是多线程却有点看不懂.
例如我十个线程分块下载,可能我每一块都在下.突然断电了.然后我再用十个线程去下载.现在的问题是这代码是怎么样保证这十个线程所下载下来的代码是怎么样组合在一起的呢?
实现原更是怎么样的呢?请高人指点.
(注:此代码是由网上一位高人提供的,不是我写的,如果能得到他的指点就更好了)谢谢大家.
/// <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(); //多线程下载
//Thread t =
new Thread(new ThreadStart(x.StartDownloadFileChunk)).Start();
//t.Start();
}
p += s;
}
s = ss;
byte[] buffer = this.ResponseAsBytes(Address, hwrp, s, 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, 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;
}
} } /// <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;
}
}
解决方案 »
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