Using SSH to transfer files in Java

In this example, I'll be using JSch library to copy a file from my local server to a remote host. If using Maven, add the following dependency to your pom.xml file:

        <!-- for ssh -->
        <dependency>
            <groupId>com.jcraft</groupId>
            <artifactId>jsch</artifactId>
            <version>${jsch.version}</version>
        </dependency>

Define an interface for your remote file operations:

public interface RemoteFileUtilities {
    public void copyFile(String filename, HostInfo hostInfo);
    public List<String> lsDir(String dir, HostInfo hostInfo);
}

SSH implementation class:

public class SshUtilities implements RemoteFileUtilities {

    @Override
    public void copyFile(String filename, HostInfo hostInfo) {
        JSch jsch = new JSch();
        Session session = null;
        ChannelSftp channel = null;
        try {
            session = jsch.getSession(hostInfo.getUsername(),
                    hostInfo.getHostname(), hostInfo.getPort());
            session.setPassword(hostInfo.getPassword());
            session.setConfig("StrictHostKeyChecking", "no");
            session.connect();
            channel = (ChannelSftp) session.openChannel("sftp");
            channel.connect();
            File localFile = new File(filename);
            // If you want you can change the directory using the following line.
            channel.cd(hostInfo.getPath());
            channel.put(new FileInputStream(localFile), localFile.getName());   
        } 
        catch (JSchException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (SftpException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        channel.disconnect();
        session.disconnect();
    }

    @Override
    public List<String> lsDir(String dir, HostInfo hostInfo) {
        JSch jsch = new JSch();
        Session session = null;
        ChannelSftp channel = null;
        try {
            session = jsch.getSession(hostInfo.getUsername(), hostInfo.getHostname(), hostInfo.getPort());
            session.setPassword(hostInfo.getPassword());
            session.setConfig("StrictHostKeyChecking", "no");
            session.connect();
            channel = (ChannelSftp) session.openChannel("sftp");
            channel.connect();
            return channel.ls(dir);  
        } 
        catch (JSchException e) {
            e.printStackTrace();
        } 
        catch (SftpException e) {
             e.printStackTrace();
        }
        channel.disconnect();
        session.disconnect();
        return null;
    }     
}

A supporting class to hold information related to your host:

public class HostInfo {
    
    private String hostname;
    private String username;
    private String password;
    private String path;
    private int port;
    
    
    public HostInfo(String hostname, String username, String password, String path, int port) {
        super();
        this.hostname = hostname;
        this.username = username;
        this.password = password;
        this.path = path;
        this.port = port;
    }
    
    public String getHostname() {
        return hostname;
    }
    public void setHostname(String hostname) {
        this.hostname = hostname;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getPath() {
        return path;
    }
    public void setPath(String path) {
        this.path = path;
    }
    public int getPort() {
        return port;
    }
    public void setPort(int port) {
        this.port = port;
    } 
}

And finally, a JUnit test class:

public class SshUtilitiesTest {

    @Test
    public void test() {
        HostInfo hostInfo = new HostInfo("dev-core-ccm-1", "noushin", "nbcg14g~", "/home/noushin/ssh-test", 22);
        SshUtilities sshUtils = new SshUtilities();
        sshUtils.copyFile("/tmp/log/error.log", hostInfo);
        List<String> files = sshUtils.lsDir(hostInfo.getPath(), hostInfo);
        if (files != null) {
            for (int i = 0; i < files.size(); i++)
                assert(files.get(i).contains("error.log"));
        }
    }
}