How to Upload a File Using FTPClient in Java?

How can I upload a file using FTPClient in Java?

import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

Using the FTPClient class from the Apache Commons Net library allows Java developers to easily connect to FTP servers and perform file uploads. This process involves establishing a connection, logging in with credentials, setting the file type, and finally uploading the file.

import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;

public class FTPUploader {
    public static void main(String[] args) {
        FTPClient ftpClient = new FTPClient();
        try {
            ftpClient.connect("ftp.example.com");
            ftpClient.login("username", "password");

            ftpClient.setFileType(FTP.BINARY_FILE_TYPE);

            FileInputStream inputStream = new FileInputStream("local-file.txt");
            boolean done = ftpClient.storeFile("remote-file.txt", inputStream);
            inputStream.close();
            if (done) {
                System.out.println("File uploaded successfully.");
            }
        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            try {
                if (ftpClient.isConnected()) {
                    ftpClient.logout();
                    ftpClient.disconnect();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }
}

Causes

• Incorrect server address
• Wrong username or password
• Insufficient permissions on the server
• Network connectivity issues

Solutions

• Ensure the FTP server address is correct.
• Double-check the username and password for authentication.
• Verify permissions for the target directory on the server.
• Check your firewall or network configuration for potential blocks.

Mistake: Not closing the input stream after the upload.

Solution: Use a try-with-resources statement or close the FileInputStream in a finally block.

Mistake: Forgetting to set the file type before upload.

Solution: Always set the file type using ftpClient.setFileType(FTP.BINARY_FILE_TYPE); for binary files.

Mistake: Using wrong file paths or names.

Solution: Ensure the local file path and remote file name are correct.