Java and FTP to edit online text files

Question

In my Java swing program, I read, edit and save various text files in a local folder using Scanner and BufferedWriter. Is there an easy way I can keep my current code, but, using FTP, edit a web file rather than a local file? Thanks everyone.

Answer 1

I tried to achieve the same and the answers to those questions helped me a lot:

Adding characters to beginning and end of InputStream in Java (the one marked as right shows how to add a custom string to the InputStream)

Uploading a file to a FTP server from android phone? (the one from Kumar Vivek Mitra shows how to upload a file)

I added new text to the end of my online file like this:

FTPClient con = null;

        try {
            con = new FTPClient();
            con.connect(Hostname);

            if (con.login(FTPUsername, FTPPassword)) {
                con.enterLocalPassiveMode(); // important!
                con.setFileType(FTP.BINARY_FILE_TYPE);

                InputStream onlineDataIS = urlOfOnlineFile.openStream();

                String end = "\nteeeeeeeeeeeeeeeeest";
                List<InputStream> streams = Arrays.asList(
                        onlineDataIS,
                        new ByteArrayInputStream(end.getBytes()));
                InputStream resultIS = new SequenceInputStream(Collections.enumeration(streams));

                // Stores a file on the server using the given name and taking input from the given InputStream.
                boolean result = con.storeFile(PathOfTargetFile, resultIS);
                onlineDataIS.close();
                resultIS.close();
                if (result) Log.v("upload result", "succeeded");
                con.logout();
                con.disconnect();
            }
            return "Writing successful";
        } catch (IOException e) {
             // some smart error handling
        }

Hope that helps.

Answer 2

You can use the URL and URLConnection classes to obtain InputStreams and OutputStreams to files located on an FTP Server.

To read a file

URL url = new URL("ftp://user:pass@my.ftphost.com/myfile.txt");
InputStream in = url.openStream();

to write a file

URL url = new URL("ftp://user:pass@my.ftphost.com/myfile.txt");
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
OutputStream out = conn.getOutputStream();