FTP, SFTP, FTPS examples In Java .

The FTP (File Transfer Protocol), FTPS (FTP over SSL), SFTP (FTP over SSH) and SCP (Secure Copy over SSH) . 

http://commons.apache.org/proper/commons-net/apidocs/org/apache/commons/net/ftp/FTPSClient.html

The examples of FTP/FTPs, the jar supporting them is org.apache.commons.net.ftp.

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.security.NoSuchAlgorithmException;
import java.util.Vector;

import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;
import org.apache.commons.net.ftp.FTPReply;
import org.apache.commons.net.ftp.FTPSClient;
import org.apache.log4j.Logger;

public class FtpClient{

	private static final Logger logger = Logger.getLogger(FtpClient.class);

	private FTPClient client;

	public FtpClient(boolean ftps) {
		if (ftps) {
			try {
				client = new FTPSClient(true);
			} catch (NoSuchAlgorithmException e) {
				e.printStackTrace();
			}
		} else {
			client = new FTPClient();
		}
	}

	public boolean changeDir(String remotePath) throws Exception {
		return client.changeWorkingDirectory(remotePath);
	}

	public boolean connect(String host, String login, String password, int port) throws Exception {
		logger.debug("FTP request connect to " + host + ":" + port);
		client.connect(host, port);
		int reply = client.getReplyCode();
		if (FTPReply.isPositiveCompletion(reply)) {
			logger.debug("FTP request login as " + login);
			if (client.login(login, password)) {
				client.enterLocalPassiveMode();
				return true;
			}
		}
		disconnect();
		return false;
	}

	public void disconnect() throws Exception {
		logger.debug("FTP request disconnect");
		client.disconnect();
	}


	protected boolean downloadFileAfterCheck(String remotePath, String localFile) throws IOException {

		boolean rst;
		FileOutputStream out = null;
		try {
			File file = new File(localFile);
			if (!file.exists()) {
				out = new FileOutputStream(localFile);
				rst = client.retrieveFile(remotePath, out);
			} else {
				rst = true;
			}
		} finally {
			if (out != null) {
				out.close();
			}
		}
		if (out != null) {
			out.close();
		}
		return rst;
	}

	protected boolean downloadFile(String remotePath, String localFile) throws IOException {

		boolean rst;
		FileOutputStream out = null;
		try {
			out = new FileOutputStream(localFile);
			rst = client.retrieveFile(remotePath, out);
		} finally {
			if (out != null) {
				out.close();
			}
		}
		return rst;
	}

	public Vector<String> listFileInDir(String remoteDir) throws Exception {
		if (changeDir(remoteDir)) {
			FTPFile[] files = client.listFiles();
			Vector<String> v = new Vector<String>();
			for (FTPFile file : files) {
				if (!file.isDirectory()) {
					v.addElement(file.getName());
				}
			}
			return v;
		} else {
			return null;
		}
	}

	public boolean uploadFile(String localFile, String remotePath) throws IOException {
		FileInputStream in = new FileInputStream(localFile);
		boolean rst;
		try {
			rst = client.storeFile(remotePath, in);
		} finally {
			in.close();
		}
		return rst;
	}

	@Override
	public Vector<String> listSubDirInDir(String remoteDir) throws Exception {
		if (changeDir(remoteDir)) {
			FTPFile[] files = client.listFiles();
			Vector<String> v = new Vector<String>();
			for (FTPFile file : files) {
				if (file.isDirectory()) {
					v.addElement(file.getName());
				}
			}
			return v;
		} else {
			return null;
		}
	}

	protected boolean createDirectory(String dirName) {
		try {
			return client.makeDirectory(dirName);
		} catch (IOException e) {
			e.printStackTrace();
		}
		return false;
	}


	public boolean isARemoteDirectory(String path) {
		String cache = "/";
		try {
			cache = client.printWorkingDirectory();
		} catch (NullPointerException e) {
			//nop
		} catch (IOException e) {
			e.printStackTrace();
		}
		try {
			boolean isDir = changeDir(path);
			changeDir(cache);
			return isDir;
		} catch (IOException e) {
			//e.printStackTrace();
		} catch (Exception e) {
			//e.printStackTrace();
		}
		return false;
	}

	public String getWorkingDirectory() {
		try {
			return client.printWorkingDirectory();
		} catch (IOException e) {
		}
		return null;
	}

}

 

the example of SFTP, the jar supporting this is com.jcraft.jsch

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public class
  
private
  
private
  
public
null;  
    }  
  
public boolean connect(String host, String login, String password, int port) throws
  
//If the client is already connected, disconnect
if (command != null) {  
            disconnect();  
        }  
new
try
"no");  
            session = SftpClientFactory.createConnection(host, port, login.toCharArray(), password.toCharArray(), fso);  
"sftp");  
            channel.connect();  
            command = (ChannelSftp) channel;  
  
catch
            e.printStackTrace();  
return false;  
        }  
return
    }  
  
public void
if (command != null) {  
            command.exit();  
        }  
if (session != null) {  
            session.disconnect();  
        }  
null;  
    }  
  
public Vector<String> listFileInDir(String remoteDir) throws
try
            Vector<LsEntry> rs = command.ls(remoteDir);  
new
for (int i = 0; i < rs.size(); i++) {  
if
                    result.add(rs.get(i).getFilename());  
                }  
            }  
return
catch
            e.printStackTrace();  
            System.err.println(remoteDir);  
throw new
        }  
    }  
  
public Vector<String> listSubDirInDir(String remoteDir) throws
        Vector<LsEntry> rs = command.ls(remoteDir);  
new
for (int i = 0; i < rs.size(); i++) {  
if
                result.add(rs.get(i).getFilename());  
            }  
        }  
return
    }  
  
protected boolean
try
            command.mkdir(dirName);  
catch
return false;  
        }  
return true;  
    }  
  
protected boolean downloadFileAfterCheck(String remotePath, String localPath) throws
null;  
try
new
if
new
                command.get(remotePath, outputSrr);  
            }  
catch
try
" not found in "
catch
                e1.printStackTrace();  
            }  
            e.printStackTrace();  
return false;  
finally
if (outputSrr != null) {  
                outputSrr.close();  
            }  
        }  
return true;  
    }  
  
protected boolean downloadFile(String remotePath, String localPath) throws
new
try
            command.get(remotePath, outputSrr);  
catch
try
" not found in "
catch
                e1.printStackTrace();  
            }  
            e.printStackTrace();  
return false;  
finally
if (outputSrr != null) {  
                outputSrr.close();  
            }  
        }  
return true;  
    }  
  
protected boolean uploadFile(String localPath, String remotePath) throws
new
try
            command.put(inputSrr, remotePath);  
catch
            e.printStackTrace();  
return false;  
finally
if (inputSrr != null) {  
                inputSrr.close();  
            }  
        }  
return true;  
    }  
  
public boolean changeDir(String remotePath) throws
try
            command.cd(remotePath);  
catch
return false;  
        }  
return true;  
    }  
  
public boolean
try
return
catch
//e.printStackTrace();
        }  
return false;  
    }  
  
public
try
return
catch
            e.printStackTrace();  
        }  
return null;  
    }  
  
}