/// <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
long num = 0;
try
{
a = Response.Headers["Content-Disposition"]; //attachment
if (a != null)
{
a = a.Substring(a.LastIndexOf("filename=") + 9);
}
num = Length; //Response.ContentLength;
bool flag = false;
if (num == -1)
{
flag = true;
num = 0x0000; //6k
}
byte[] buffer = new byte[(int)num];
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.Toint(s);
}
num = 0;
Stream S = Response.GetResponseStream();
do
{
num = S.Read(buffer, num, ((int)num) - num);
num += num;
if (flag && (num == num))
{
num += 0x0000;
byte[] buffer = new byte[(int)num];
Buffer.BlockCopy(buffer, 0, buffer, 0, num);
buffer = buffer;
}
// lock (_SyncLockObject)
// {
// this._bytes += num;
// }
if (num > 0)
{
if (this.DataReceive != null)
{
byte[] buffer = new byte[num];
Buffer.BlockCopy(buffer, p, buffer, 0, buffer.Length);
DownLoadState dls = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, num, buffer);
DownLoadEventArgs dlea = new DownLoadEventArgs(dls);
//触发事件
this.OnDataReceive(dlea);
//System.Threading.Thread.Sleep(00);
}
p += num; //本块的位置指针
P += num; //整个文件的位置指针
}
else
{
break;
}
}while (num != 0);
S.Close();
S = null;
if (flag)
{
byte[] buffer = new byte[num];
Buffer.BlockCopy(buffer, 0, buffer, 0, num);
buffer = buffer;
}
return(buffer);
}
catch (Exception e)
{
ExceptionActions ea = ExceptionActions.Throw;
if (this.ExceptionOccurrs != null)
{
DownLoadState x = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, num);
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);
}
}
/// <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; //Int.MaxValue 该常数的值为 ,7,8,67; 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 < 0x60) //块大小至少为 8 K 字节
{
s = 0x60;
}
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;
}
}
}
