Connecting to an SFTP Server Using Java JSch Library

JSch (Java Secure Channel) is a popular Java library that allows developers to connect to remote servers over SSH and perform secure file transfers using the SFTP (Secure File Transfer Protocol). It is widely used for automating file transfers, remote command execution, and secure authentication.

Step-by-Step Process

Step 1: Add JSch Library to Your Project

Java does not provide built-in support for SFTP connections, so we need to include the JSch library in your project.

If we are using Maven, add this dependency in pom.xml:

Step 2: Establish a Connection to the SFTP Server

Before performing file operations, we need to establish an SSH session and an SFTP channel using JSch.

Steps

1. Create a JSch instance: This is the entry point for SSH communication.
2. Create a session: Provide the SFTP server hostname, port, username, and password.
3. Configure the session: Disable "StrictHostKeyChecking" to prevent host verification errors.
4. Connect to the SFTP server.
5. Open an SFTP channel: Required for file transfer operations.
6. Close the connection after use.

Step 3: Upload a File to the SFTP Server

Once connected to the server, we can upload a file using the put() method of ChannelSftp.

Steps

1. Connect to the server (same as Step 2).
2. Specify the local file path (file to upload).
3. Specify the remote directory (destination folder on the server).
4. Use put() method to transfer the file.
5. Close the connection after completion.

Step 4: Download a File from the SFTP Server

To download a file, we use the get() method that transfers the file from the SFTP server to our local machine.

Steps

1. Connect to the SFTP server.
2. Specify the remote file path (file to download).
3. Specify the local directory (where to save the file).
4. Use get() method to download the file.
5. Close the connection.