C# 如何使用 HttpWebRequest/Response 从 Web 服务器下载二进制 (.exe) 文件？
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How To Use HttpWebRequest/Response To Download A Binary (.exe) File From A Web Server?
提问by Jan Tacci
I am writing a program that needs to download an .exefile from a website and then save it to the hard drive. The .exeis stored on my site and it's url is as follows (it's not the real uri just one I made up for the purpose of this question):
我正在编写一个程序，需要.exe从网站下载文件，然后将其保存到硬盘驱动器。将.exe存储在我的网站，它的网址如下（这不是真正的URI只是一个我提出了对这个问题的目的）：
http://www.mysite.com/calc.exe
After many web searches and fumbling through examples here is the code I have come up with so far:
经过多次网络搜索和摸索示例之后，我到目前为止想出了代码：
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(http://www.mysite.com/calc.exe);
HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse();
Stream responseStream = webResponse.GetResponseStream();
StreamReader streamReader = new StreamReader(responseStream);
string s = streamReader.ReadToEnd();
As you can see I am using the StreamReaderclass to read the data. After calling ReadToEnddoes the stream reader contain the (binary) content of my .exe? Can I just write the content of the StreamReaderto a file (named calc.exe) and I will have succesfully downloaded the .exe?
如您所见，我正在使用StreamReader该类来读取数据。调用后ReadToEnd流阅读器是否包含我的 .exe 的（二进制）内容？我可以StreamReader将 .exe的内容写入文件（名为 calc.exe），然后成功下载 .exe 吗？
I am wondering why StreamReaderReadToEndreturns a string. In my case would this string be the binary content of calc.exe?
我想知道为什么StreamReaderReadToEnd返回一个字符串。在我的情况下，这个字符串是 calc.exe 的二进制内容吗？
回答by VinayC
StreamReaderis a text reader implementation i.e. it should be used to read text data and not binary data. In your case, you should be directly using the underlying response stream.
StreamReader是一个文本阅读器实现，即它应该用于读取文本数据而不是二进制数据。在您的情况下，您应该直接使用底层响应流。
For downloading file, the simplest way would be to use WebClient.DownloadFilemethod.
对于下载文件，最简单的方法是使用WebClient.DownloadFile方法。
回答by dotNET
Instead of using StreamReader, you should really call Read()method of your Streamobject. That will ask you for a byte[] buffer to be fill with read data, which you can then write to disk using StreamWriteror FileStream.
StreamReader您应该真正调用对象的Read()方法，而不是使用Stream。这将要求您使用 byte[] 缓冲区填充读取数据，然后您可以使用StreamWriteror将其写入磁盘FileStream。
回答by user2492339
This should directly save the file on your hard disk.
这应该直接将文件保存在您的硬盘上。
using System.Net;
using (WebClient webClient = new WebClient ())
{
webClient.DownloadFile("http://www.mysite.com/calc.exe", "calc.exe");
}
回答by Dipu
WebClient is the best method to download file. But you can use the following method to download a file asynchronously from web server.
WebClient 是下载文件的最佳方法。但是您可以使用以下方法从 Web 服务器异步下载文件。
private static void DownloadCurrent()
{
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create("[url to download]");
webRequest.Method = "GET";
webRequest.Timeout = 3000;
webRequest.BeginGetResponse(new AsyncCallback(PlayResponeAsync), webRequest);
}
private static void PlayResponeAsync(IAsyncResult asyncResult)
{
long total = 0;
long received = 0;
HttpWebRequest webRequest = (HttpWebRequest)asyncResult.AsyncState;
try
{
using (HttpWebResponse webResponse = (HttpWebResponse)webRequest.EndGetResponse(asyncResult))
{
byte[] buffer = new byte[1024];
FileStream fileStream = File.OpenWrite("[file name to write]");
using (Stream input = webResponse.GetResponseStream())
{
total = input.Length;
int size = input.Read(buffer, 0, buffer.Length);
while (size > 0)
{
fileStream.Write(buffer, 0, size);
received += size;
size = input.Read(buffer, 0, buffer.Length);
}
}
fileStream.Flush();
fileStream.Close();
}
}
catch (Exception ex)
{
}
}
There is a similar thread here - how to download the file using httpwebrequest
这里有一个类似的线程 -如何使用 httpwebrequest 下载文件
回答by ThexBasic
I'm probably a little bit late but I had the same problem with files being always 0kb big if not running in Debug mode.. This might be a relatively simple answer but disabling "DEBUG-Constants" under Properties solved it for me.
我可能有点晚了，但我遇到了同样的问题，如果不在调试模式下运行，文件总是 0kb 大。这可能是一个相对简单的答案，但在属性下禁用“DEBUG-Constants”为我解决了这个问题。
