Question

request = MakeConnection(uri, WebRequestMethods.Ftp.DownloadFile, username, password);
response = (FtpWebResponse)request.GetResponse();
Stream responseStream = response.GetResponseStream();

//This part of the code is  used to write the read content from the server
using (StreamReader responseReader = new StreamReader(responseStream))
{
    using (var destinationStream = new FileStream(toFilenameToWrite, FileMode.Create))
    {
        byte[] fileContents = Encoding.UTF8.GetBytes(responseReader.ReadToEnd());
        destinationStream.Write(fileContents, 0, fileContents.Length);
    }
}

//This part of the code is  used to write the read content from the server
using (var destinationStream = new FileStream(toFilenameToWrite, FileMode.Create))
{
    long length = response.ContentLength;
    int bufferSize = 2048;
    int readCount;
    byte[] buffer = new byte[2048];
    readCount = responseStream.Read(buffer, 0, bufferSize);
    while (readCount > 0)
    {
        destinationStream.Write(buffer, 0, readCount);
        readCount = responseStream.Read(buffer, 0, bufferSize);
    }
}

前者将内容写入文件，但是当我尝试打开文件时，它说它已损坏。但是后者在下载zip文件时完成了这项工作。有没有具体的原因为什么前一个代码不适用于zip文件，因为它适用于文本文件？

Answer 1

byte[] fileContents = Encoding.UTF8.GetBytes(responseReader.ReadToEnd());

您尝试将二进制PDF文件解释为UTF-8文本。那是行不通的。

要获得正确的代码，请参阅Upload and download a binary file to/from FTP server in C#/.NET。

Answer 2

使用BinaryWriter并将其传递给FileStream。

    //This part of the code is  used to write the read content from the server
    using (var destinationStream = new BinaryWriter(new FileStream(toFilenameToWrite, FileMode.Create)))
    {
        long length = response.ContentLength;
        int bufferSize = 2048;
        int readCount;
        byte[] buffer = new byte[2048];
        readCount = responseStream.Read(buffer, 0, bufferSize);
        while (readCount > 0)
        {
            destinationStream.Write(buffer, 0, readCount);
            readCount = responseStream.Read(buffer, 0, bufferSize);
        }
    }

Answer 3

这是我的解决方案，对我有用

<强> C＃

public IActionResult GetZip([FromBody] List<DocumentAndSourceDto> documents)
{
    List<Document> listOfDocuments = new List<Document>();

    foreach (DocumentAndSourceDto doc in documents)
        listOfDocuments.Add(_documentService.GetDocumentWithServerPath(doc.Id));

    using (var ms = new MemoryStream())
    {
        using (var zipArchive = new ZipArchive(ms, ZipArchiveMode.Create, true))
        {
            foreach (var attachment in listOfDocuments)
            {
                var entry = zipArchive.CreateEntry(attachment.FileName);

                using (var fileStream = new FileStream(attachment.FilePath, FileMode.Open))
                using (var entryStream = entry.Open())
                {
                    fileStream.CopyTo(entryStream);
                }
            }

        }
        ms.Position = 0;
        return File(ms.ToArray(), "application/zip");
    }

    throw new ErrorException("Can't zip files");
}

不要错过ms.Position = 0;这里

从C＃中的服务器下载后，Zip文件已损坏

3 个答案: