java - FTP 列表命令抛出 MalformedServerReplyException : Truncated server reply

Question

我有一个使用 Apache Commons Net 将 mp3 上传到我的 FTP 服务器的 Java 应用程序。

但是，如果是新文件，则会抛出MalformedServerReplyException。如果是现有文件，它将完美上传并覆盖。

异常已经在行抛出:

ftpClient.setFileType(FTP.BINARY_FILE_TYPE);

但是，我检查了 Wireshark 并且命令 TYPE I 正常。

有人可以帮我解决这个问题吗？

这是异常之前的 Wireshark 图像:

public static void transferFile(File file, boolean OverwriteAllowed) {
    FtpLogin();
    try {
        System.out.println('\n');
        System.out.println("DEBUG: "+ file.toString());

        boolean isNewFile = false;
        String filePath = getFtpPathToMusic() + file.getName();

        ftpClient.sendNoOp();
        showServerReply();

        if (ftpClient.listFiles(filePath).length > 0) {
            System.out.println("File exists, and overwrite allowed is: " + OverwriteAllowed);
        } else {
            isNewFile = true;
          //  System.out.println("File does not exist yet on server");
        }

        if (OverwriteAllowed || isNewFile) {
            ftpClient.setStrictReplyParsing(false);
            ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
            showServerReply();
            InputStream inputStream = new FileInputStream(file);


            OutputStream outputStream = ftpClient.storeFileStream(filePath);
            byte[] bytesIn = new byte[4096];
            int read;
            long remaining = file.length();
            long transferred = 0;

            System.out.println("Transfering data...");
            while ((read = inputStream.read(bytesIn)) != -1) {
                outputStream.write(bytesIn, 0, read);
                remaining -= read;
                transferred += read;
                System.out.print('\r');
                System.out.print("Remaining: " + remaining/1024 + "kb | Transferred: " + transferred/1024 + "kb");
            }
            System.out.println();
            inputStream.close();
            outputStream.close();

            boolean completed = ftpClient.completePendingCommand();
            if (completed) {
                showServerReply();
                System.out.println("File " + filePath + " uploaded succesfully");
            }
        } else {
            System.out.println("File is skipped");
        }
    } catch (IOException e) {
        e.printStackTrace();
        showServerReply();
    }

}

预期:上传成功
实际:MalformedServerReplyException

org.apache.commons.net.MalformedServerReplyException: Truncated server reply: 
at org.apache.commons.net.ftp.FTP.__getReply(FTP.java:332)
at org.apache.commons.net.ftp.FTP.__getReply(FTP.java:300)
at org.apache.commons.net.ftp.FTP.sendCommand(FTP.java:523)
at org.apache.commons.net.ftp.FTP.sendCommand(FTP.java:648)
at org.apache.commons.net.ftp.FTP.type(FTP.java:1119)
at org.apache.commons.net.ftp.FTPClient.setFileType(FTPClient.java:1559)
at FtpSupport.FtpTransfer.transferFile(FtpTransfer.java:116)
at Home.ConverterGuiHome$convertMp3FilesExecute.actionPerformed(ConverterGuiHome.java:144)

应要求 - 完整的 (FTP) 日志记录:

Getting files from: /ideaProjects/GsmMp3Manager/src/main/Mp3Files/export
Creating mp3 object from file: 377 test.mp3
220 DiskStation FTP server ready.
SERVER: 220 DiskStation FTP server ready.
NOOP
200 NOOP command successful.
SERVER: 200 NOOP command successful.
USER *******
331 Password required for Barbet.
PASS *******
230 User Barbet logged in.
SERVER: 230 User Barbet logged in.
LOGGED IN SERVER
File listing in directory  :
SYST
215 UNIX Type: L8
PASV
227 Entering Passive Mode (77,164,214,202,216,242)
LIST 
150 Opening BINARY mode data connection for 'file list'.
226 Transfer complete.
[home]      4096        2018-12-12 00:00:00
[Spotlight]     4096        2018-11-17 00:00:00
[music]     4096        2018-11-22 00:00:00
[Mission Possible]      4096        2013-11-13 00:00:00
DEBUG:377 test.mp3


DEBUG: src/main/Mp3Files/export/377 test.mp3
NOOP
200 NOOP command successful.
SERVER: 200 NOOP command successful.
PASV
227 Entering Passive Mode (77,164,214,202,216,241)
LIST /Spotlight/muziek/377 test.mp3
150 Opening BINARY mode data connection for 'file list'.
550 /Spotlight/muziek/377 test.mp3: No such file or directory.
TYPE I
org.apache.commons.net.MalformedServerReplyException: Truncated server reply: 
    at org.apache.commons.net.ftp.FTP.__getReply(FTP.java:332)
    (... see stack trace)

 Close ftp session
QUIT
200 Type set to I.
SERVER: 200 Type set to I.

Answer 1

必须通过完整的 Wireshark 转储来确认，但我相信日志文件表明 550 对 LIST 命令的响应后跟两个换行符。 Apache FTPClient 将第二个“行”视为对以下 TYPE I 命令的(无效)响应。所以它看起来像是一个服务器端错误。

您是否尝试过使用其他方法来检查文件是否存在？
请参阅我对 Checking file existence on FTP server 的回答
(正如答案所说，使用 listFiles 检查文件是否存在实际上违反了 FTP 协议(protocol))。