Asp.net 用C语言下载小块的大文件#
我需要下载一些大于25MB的文件,但我的网络只允许请求25MB的文件 我正在使用以下代码Asp.net 用C语言下载小块的大文件#,asp.net,c#-4.0,httpwebrequest,websocket,Asp.net,C# 4.0,Httpwebrequest,Websocket,我需要下载一些大于25MB的文件,但我的网络只允许请求25MB的文件 我正在使用以下代码 const long DefaultSize = 26214400; long Chunk = 26214400; long offset = 0; byte[] bytesInStream; public void Download(string url, string filename) { long size = Size(url);
const long DefaultSize = 26214400;
long Chunk = 26214400;
long offset = 0;
byte[] bytesInStream;
public void Download(string url, string filename)
{
long size = Size(url);
int blocksize = Convert.ToInt32(size / DefaultSize);
int remainder = Convert.ToInt32(size % DefaultSize);
if (remainder > 0) { blocksize++; }
FileStream fileStream = File.Create(@"D:\Download TEST\" + filename);
for (int i = 0; i < blocksize; i++)
{
if (i == blocksize - 1)
{
Chunk = remainder;
}
HttpWebRequest req = (HttpWebRequest)System.Net.WebRequest.Create(url);
req.Method = "GET";
req.AddRange(Convert.ToInt32(offset), Convert.ToInt32(Chunk+offset));
HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
// StreamReader sr = new StreamReader(resp.GetResponseStream());
using (Stream responseStream = resp.GetResponseStream())
{
bytesInStream = new byte[Chunk];
responseStream.Read(bytesInStream, 0, (int)bytesInStream.Length);
// Use FileStream object to write to the specified file
fileStream.Seek((int)offset, SeekOrigin.Begin);
fileStream.Write(bytesInStream,0, bytesInStream.Length);
}
offset += Chunk;
}
fileStream.Close();
}
public long Size(string url)
{
System.Net.WebRequest req = System.Net.HttpWebRequest.Create(url);
req.Method = "HEAD";
System.Net.WebResponse resp = req.GetResponse();
resp.Close();
return resp.ContentLength;
}
const long DefaultSize=26214400;
长块=26214400;
长偏移=0;
字节[]字节流内;
公共无效下载(字符串url、字符串文件名)
{
长尺寸=尺寸(url);
int blocksize=Convert.ToInt32(大小/默认大小);
整数余数=Convert.ToInt32(大小%DefaultSize);
如果(余数>0){blocksize++;}
FileStream FileStream=File.Create(@“D:\Download TEST\”+文件名);
对于(int i=0;i
它可以正确地将内容写入磁盘,但内容不起作用您应该在写入之前检查读取了多少,类似这样的内容(您不需要记住查找的偏移量,写入时自动查找):
有一个类似的问题可能会帮助你 及 还有这篇代码项目文章
范围是从零开始的,你应该从上限中减去1
request.Headers.Range = new System.Net.Http.Headers.RangeHeaderValue(offset, chunkSize + offset - 1);
我在以下链接发布了正确的代码片段:
Akka streams可以使用多线程技术从System.IO.Stream中以小块形式下载文件 下载方法将把字节附加到以long fileStart开头的文件中。如果文件不存在,fileStart值必须为0
using Akka.Actor;
using Akka.IO;
using Akka.Streams;
using Akka.Streams.Dsl;
using Akka.Streams.IO;
private static Sink<ByteString, Task<IOResult>> FileSink(string filename)
{
return Flow.Create<ByteString>()
.ToMaterialized(FileIO.ToFile(new FileInfo(filename), FileMode.Append), Keep.Right);
}
private async Task Download(string path, Uri uri, long fileStart)
{
using (var system = ActorSystem.Create("system"))
using (var materializer = system.Materializer())
{
HttpWebRequest request = WebRequest.Create(uri) as HttpWebRequest;
request.AddRange(fileStart);
using (WebResponse response = request.GetResponse())
{
Stream stream = response.GetResponseStream();
await StreamConverters.FromInputStream(() => stream, chunkSize: 1024)
.RunWith(FileSink(path), materializer);
}
}
}
使用Akka.Actor;
使用Akka.IO;
使用Akka.Streams;
使用Akka.Streams.Dsl;
使用Akka.Streams.IO;
专用静态接收器文件链接(字符串文件名)
{
返回流。创建()
.ToMaterialized(FileIO.ToFile(新的FileInfo(filename)、FileMode.Append)、Keep.Right);
}
私有异步任务下载(字符串路径、Uri、长文件启动)
{
使用(var system=ActorSystem.Create(“系统”))
使用(var materializer=system.materializer())
{
HttpWebRequest-request=WebRequest.Create(uri)为HttpWebRequest;
AddRange(fileStart);
使用(WebResponse=request.GetResponse())
{
Stream=response.GetResponseStream();
等待StreamConverters.FromInputStream(()=>stream,chunkSize:1024)
.RunWith(文件链接(路径),物化器);
}
}
}
我真的无法提供答案,但您是否能够逐步完成代码?我建议缩小所有数字(例如,将最大块大小设置为10字节,下载文件大小设置为25字节),然后逐步执行。由于涉及到更小的块,可能更容易发现哪里出了问题。你有没有找到最终的解决方案,并开始工作?回答:它仍然不工作
你说
using Akka.Actor;
using Akka.IO;
using Akka.Streams;
using Akka.Streams.Dsl;
using Akka.Streams.IO;
private static Sink<ByteString, Task<IOResult>> FileSink(string filename)
{
return Flow.Create<ByteString>()
.ToMaterialized(FileIO.ToFile(new FileInfo(filename), FileMode.Append), Keep.Right);
}
private async Task Download(string path, Uri uri, long fileStart)
{
using (var system = ActorSystem.Create("system"))
using (var materializer = system.Materializer())
{
HttpWebRequest request = WebRequest.Create(uri) as HttpWebRequest;
request.AddRange(fileStart);
using (WebResponse response = request.GetResponse())
{
Stream stream = response.GetResponseStream();
await StreamConverters.FromInputStream(() => stream, chunkSize: 1024)
.RunWith(FileSink(path), materializer);
}
}
}