我一直在尝试用C#编写一个程序,像大多数下载管理器一样,使用多个段一次下载一个文件,但我遇到了下载的文件被损坏的问题。例如,我下载了一个视频,它播放了2秒,然后WMP说它无法播放。
我对下载的文件进行了六进制编辑,似乎有零字节的部分散布在整个文件中,有人知道为什么吗?VS没有报告错误。
在单独的线程中为每个段调用getPart()。
public long start;
public long end;
public int thread;
public Form1 handle;
public myFile handler;
public void getPart()
{
log("getting part " + start.ToString() + "," + end.ToString());
HttpWebRequest part = (HttpWebRequest)WebRequest.Create(handler.url);
part.AddRange((int)start,(int) end);
HttpWebResponse pr = (HttpWebResponse)part.GetResponse();
Stream rstream = pr.GetResponseStream();
log("Beginning part " + start.ToString());
int totalbytes = 0;
byte[] buffer = new byte[256];
int x = rstream.Read(buffer, 0, 256);
while (x > 0)
{
handler.writeFile(buffer, (int)(totalbytes + start), x);
totalbytes += x;
x = rstream.Read(buffer, 0, 256);
}
log(start.ToString() + "-byte start part done...");
rstream.Close();
pr.Close();
handler.partDone(thread);
return;
}
public void writeFile(byte[] buffer, int start, int size)
{
mFileStream.Seek(start, SeekOrigin.Begin);
mFileStream.Write(buffer, 0, size);
return;
}发布于 2009-12-03 07:15:08
好吧,我已经弄明白了,只是想给有类似问题的人留下一个答案。文件写入流周围需要一个锁。
public void writeFile(byte[] buffer, int start, int size)
{
mFileStream.Seek(start, SeekOrigin.Begin);
mFileStream.Write(buffer, 0, size);
return;
}变成了
public void writeFile(byte[] buffer, int start, int size)
{
lock (mFileStream)
{
mFileStream.Seek(start, SeekOrigin.Begin);
mFileStream.Write(buffer, 0, size);
return;
}
}https://stackoverflow.com/questions/1831279
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