Uploading byte array to FTP in Java

Question

My goal is to be able to upload files to FTP server, I have researched a bit and saw the way how to upload a file if the file is already stored locally, I have a function that returns byte[] so I am wondering how to send that file to FTP server if it file exist in memory.

private void connect() throws IOException {
    FTPClient ftpClient = new FTPClient();
    ftpClient.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out)));
    ftpClient.connect(ftp.getServer(), ftp.getPort());
    int reply = ftpClient.getReplyCode();
    if (!FTPReply.isPositiveCompletion(reply)) {
        ftpClient.disconnect();
        throw new RuntimeException("Could not connect to FTP Server");
    } else {
        ftpClient.login(ftp.getUser(), ftp.getPassword());
    }
}

Answer 1

You seem to be using Apache Commons Net FTPClient.

It actually does not even have a direct way to upload a physical file. Its FTPClient.storeFile method only accepts InputStream interface.

Normally you would use FileInputStream to refer to a physical file:
How do you upload a file to an FTP server?

While you want to to use ByteArrayInputStream:
Can we convert a byte array into an InputStream in Java?

InputStream inputStream = new ByteArrayInputStream(bytes);
ftpClient.storeFile(remotePath, inputStream);