scp transfer via java

I ended up using Jsch- it was pretty straightforward, and seemed to scale up pretty well (I was grabbing a few thousand files every few minutes).

plug: sshj is the only sane choice! See these examples to get started: download, upload.

Take a look here

That is the source code for Ants' SCP task. The code in the "execute" method is where the nuts and bolts of it are. This should give you a fair idea of what is required. It uses JSch i believe.

Alternatively you could also directly execute this Ant task from your java code.

The openssh project lists several Java alternatives, Trilead SSH for Java seems to fit what you're asking for.

Here is an example to upload a file using JSch:

ScpUploader.java:

import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
import com.jcraft.jsch.SftpException;

import java.io.ByteArrayInputStream;
import java.util.Properties;

public final class ScpUploader
{
    public static ScpUploader newInstance()
    {
        return new ScpUploader();
    }

    private volatile Session session;
    private volatile ChannelSftp channel;

    private ScpUploader(){}

    public synchronized void connect(String host, int port, String username, String password) throws JSchException
    {
        JSch jsch = new JSch();

        Properties config = new Properties();
        config.put("StrictHostKeyChecking", "no");

        session = jsch.getSession(username, host, port);
        session.setPassword(password);
        session.setConfig(config);
        session.setInputStream(System.in);
        session.connect();

        channel = (ChannelSftp) session.openChannel("sftp");
        channel.connect();
    }

    public synchronized void uploadFile(String directoryPath, String fileName, byte[] fileBytes, boolean overwrite) throws SftpException
    {
        if(session == null || channel == null)
        {
            System.err.println("No open session!");
            return;
        }

        // a workaround to check if the directory exists. Otherwise, create it
        channel.cd("/");
        String[] directories = directoryPath.split("/");
        for(String directory : directories)
        {
            if(directory.length() > 0)
            {
                try
                {
                    channel.cd(directory);
                }
                catch(SftpException e)
                {
                    // swallowed exception

                    System.out.println("The directory (" + directory + ") seems to be not exist. We will try to create it.");

                    try
                    {
                        channel.mkdir(directory);
                        channel.cd(directory);
                        System.out.println("The directory (" + directory + ") is created successfully!");
                    }
                    catch(SftpException e1)
                    {
                        System.err.println("The directory (" + directory + ") is failed to be created!");
                        e1.printStackTrace();
                        return;
                    }

                }
            }
        }

        channel.put(new ByteArrayInputStream(fileBytes), directoryPath + "/" + fileName, overwrite ? ChannelSftp.OVERWRITE : ChannelSftp.RESUME);
    }

    public synchronized void disconnect()
    {
        if(session == null || channel == null)
        {
            System.err.println("No open session!");
            return;
        }

        channel.exit();
        channel.disconnect();
        session.disconnect();

        channel = null;
        session = null;
    }
}

AppEntryPoint.java:

import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.SftpException;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;

public final class AppEntryPoint
{
    private static final String HOST = "192.168.1.1";
    private static final int PORT = 22;
    private static final String USERNAME = "root";
    private static final String PASSWORD = "root";

    public static void main(String[] args) throws IOException
    {
        ScpUploader scpUploader = ScpUploader.newInstance();

        try
        {
            scpUploader.connect(HOST, PORT, USERNAME, PASSWORD);
        }
        catch(JSchException e)
        {
            System.err.println("Failed to connect the server!");
            e.printStackTrace();
            return;
        }

        System.out.println("Successfully connected to the server!");

        byte[] fileBytes = Files.readAllBytes(Paths.get("C:/file.zip"));

        try
        {
            scpUploader.uploadFile("/test/files", "file.zip", fileBytes, true); // if overwrite == false, it won't throw exception if the file exists
            System.out.println("Successfully uploaded the file!");
        }
        catch(SftpException e)
        {
            System.err.println("Failed to upload the file!");
            e.printStackTrace();
        }

        scpUploader.disconnect();
    }
}

I use this SFTP API which has SCP called Zehon, it's great, so easy to use with a lot of sample code. Here is the site http://www.zehon.com

-: Refining Fernando's answer a little, if you use Maven for dependency management :-

pom.xml:

<dependency>
  <groupId>org.apache.ant</groupId>
  <artifactId>ant-jsch</artifactId>
  <version>${ant-jsch.version}</version>
</dependency>

Add this dependency in your project. Latest version can be found here.

Java code:

public void scpUpload(String source, String destination) {
    Scp scp = new Scp();
    scp.setPort(port);
    scp.setLocalFile(source);
    scp.setTodir(username + ":" + password + "@" + host + ":" + destination);
    scp.setProject(new Project());
    scp.setTrust(true);
    scp.execute();
}

I need to copy folder recursively, after trying different solutions, finally end up by ProcessBuilder + expect/spawn

scpFile("192.168.1.1", "root","password","/tmp/1","/tmp");

public void scpFile(String host, String username, String password, String src, String dest) throws Exception {

    String[] scpCmd = new String[]{"expect", "-c", String.format("spawn scp -r %s %s@%s:%s\n", src, username, host, dest)  +
            "expect \"?assword:\"\n" +
            String.format("send \"%s\\r\"\n", password) +
            "expect eof"};

    ProcessBuilder pb = new ProcessBuilder(scpCmd);
    System.out.println("Run shell command: " + Arrays.toString(scpCmd));
    Process process = pb.start();
    int errCode = process.waitFor();
    System.out.println("Echo command executed, any errors? " + (errCode == 0 ? "No" : "Yes"));
    System.out.println("Echo Output:\n" + output(process.getInputStream()));
    if(errCode != 0) throw new Exception();
}