Docker 中的 Apache FTP 客户端 运行 从外部服务器检索文件内容时出现问题

Question

我使用 Apache FTP 客户端从 FTP 服务器检索文件内容。它 运行 在被动模式下，使用 retrieveFileStream 或 retrieveFile 检索，当我 运行 它没有 Docker。当我从 Docker 容器 运行 这个应用程序时出现问题。它正确连接、登录、检索文件列表。它在检索文件内容时出现问题 - 它无法检索文件的全部内容，只能检索其中的一部分。我认为这可能是一个缓冲区问题，我将所有缓冲区设置的值设置为巨大的数字，并且还尝试使用缓冲区从流中读取（正如有人在检索文件时遇到问题时在 Whosebug 上提出的那样），但没有成功。我还将 Docker 的 MTU 设置设置为我的正常网络使用的值，但它也没有帮助。

这是一些代码：

    FTPClient ftpClient = new FTPClient();
    ftpClient.setControlKeepAliveTimeout(120);
    ftpClient.setDataTimeout(120000);
    ftpClient.setBufferSize(1024000);
    ftpClient.setReceiveBufferSize(1024000);
    ftpClient.setReceieveDataSocketBufferSize(1024000);
    LOGGER.trace("Trying to connect to host {}.", connectionSettings.getHost());
    ftpClient.connect(connectionSettings.getHost());
    int replyCode = ftpClient.getReplyCode();
    if (!FTPReply.isPositiveCompletion(replyCode)) {
        ftpClient.disconnect();
        LOGGER.error("Received negative reply code from host {}. Disconnected.", connectionSettings.getHost());
        throw new FtpClientNotReadyException();
    }

    ftpClient.enterLocalPassiveMode();

    LOGGER.trace("Received positive reply from host {}. Trying to log in.", connectionSettings.getHost());
    try {
        if (!ftpClient.login(connectionSettings.getUsername(), connectionSettings.getPassword())) {
            LOGGER.warn("FTP Client login failed for user {}", connectionSettings.getUsername());
            ftpClient.disconnect();
            throw new FtpClientNotReadyException();
        }
    } catch (IOException e) {
        ftpClient.disconnect();
        throw e;
    }
    LOGGER.trace("Successfully logged in to host {} on account {}.", connectionSettings.getHost(),
            connectionSettings.getUsername());
    try {
        if (Strings.isNotBlank(connectionSettings.getWorkingDirectory()) &&
                !ftpClient.changeWorkingDirectory(connectionSettings.getWorkingDirectory())) {
            LOGGER.warn("FTP Client could not change worked directory to {}.", connectionSettings.getWorkingDirectory());
            throw new FtpClientNotReadyException();
        }
    } catch (IOException e) {
        ftpClient.logout();
        ftpClient.disconnect();
        throw e;
    }
 InputStream retrievedFileContentInputStream = ftpClient.retrieveFileStream(fileName);

        byte[] fileContentByteArray = retrievedFileContentInputStream.readAllBytes();
        retrievedFileContentInputStream.close();
        try {
            checkFileSize(fileName, expectedFileSize, fileContentByteArray.length);
        } catch (FileCorruptedException | FileBeingCurrentlyUploadedException e) {
            throw e;
        } finally {
            if (!ftpClient.completePendingCommand()) {
                LOGGER.trace("Complete pending command was not successful.");
            }
            LOGGER.trace("Completed pending command.");
        }

这些是我尝试过的解决方案： 1) 从 InputStream 读取的缓冲区：

InputStream ins = ftpClient.retrieveFileStream(fileName);
    ByteArrayOutputStream swapStream = new ByteArrayOutputStream();
    byte[] buff = new byte[2048];
    int rc = 0;
    int value =2048;
    while ((rc = ins.read(buff, 0, value)) > 0) {
        swapStream.write(buff, 0, rc);
    }
    byte[] fileByte = swapStream.toByteArray();
    ftpClient.completePendingCommand();

2) 将输出流更改为输入流

        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        ftpClient.retrieveFile(fileName, outputStream);
        outputStream.close();
        byte[] fileContentByteArray = outputStream.toByteArray();

出现问题时我的典型日志输出：

Retrieved file size is lower than expected. Was: 228098. Expected: 236826.

Retrieved file size is lower than expected. Was: 1199. Expected: 1246.

Answer 1

由于 FTP 服务器以 ASCII 模式发送的不同行尾（回车符 return），与 Windows 不同平台上的客户端收到的字节数较少。