Question

I’m trying to retrieve a file from a server using SFTP (as opposed to FTPS) using Java. How can I do this?

Answer 1

Another option is to consider looking at the JSch library. JSch seems to be the preferred library for a few large open source projects, including Eclipse, Ant and Apache Commons HttpClient, amongst others.

It supports both user/pass and certificate-based logins nicely, as well as all a whole host of other yummy SSH2 features.

Here’s a simple remote file retrieve over SFTP. Error handling is left as an exercise for the reader 🙂

JSch jsch = new JSch();  String knownHostsFilename = '/home/username/.ssh/known_hosts'; jsch.setKnownHosts( knownHostsFilename );  Session session = jsch.getSession( 'remote-username', 'remote-host' );     {   // 'interactive' version   // can selectively update specified known_hosts file    // need to implement UserInfo interface   // MyUserInfo is a swing implementation provided in    //  examples/Sftp.java in the JSch dist   UserInfo ui = new MyUserInfo();   session.setUserInfo(ui);    // OR non-interactive version. Relies in host key being in known-hosts file   session.setPassword( 'remote-password' ); }  session.connect();  Channel channel = session.openChannel( 'sftp' ); channel.connect();  ChannelSftp sftpChannel = (ChannelSftp) channel;  sftpChannel.get('remote-file', 'local-file' ); // OR InputStream in = sftpChannel.get( 'remote-file' );   // process inputstream as needed  sftpChannel.exit(); session.disconnect();