Not Reading bytes properly during FTP transfer in Spring Batch

Question

I am doing a project where I have to efficiently transfer data(any file) from one endpoint(HTTP, FTP, SFTP) to other. I want to use springBatch concurrency and parallelism feature of Job. In my case, one file will be one job. So, I am Trying to read file(any extension) from ftp(running locally) and writing it to same ftp in different folder.

My Reader has:

FlatFileItemReader<byte[]> reader = new FlatFileItemReader<>();
reader.setResource(new UrlResource("ftp://localhost:2121/source/1.txt"));
reader.setLineMapper((line, lineNumber) -> {
            return line.getBytes();
        });

And Writer has:

URL url = new URL("ftp://localhost:2121/dest/tempOutput/TransferTest.txt");
URLConnection conn = url.openConnection();
DataOutputStream out = new DataOutputStream(conn.getOutputStream());
for (byte[] b : bytes) {  //I am getting List<byte[]> in my writer
   out.write(b);
}
out.close();

In case of text file, all content is showing in one line(omitting nextLine character) and in case of video file bytes are missing/corrupted as video is not getting played at destination.

What I am doing wrong or is there something better way to transfer file(irrespective of its extension).