How to download folder from SFTP Server (Secure File Transfer Protocol) is the common use case for Java developer who wants to download folder from SFTP. To write a java program to download from SFTP, you will need to download JSCH jar file.
For other SFTP operations in java, please refer below posts on Kodehelp.com –
Below Java program is for downloading folder/directory content recursively from SFTP server.
/**
* Created on Dec 27, 2016 Copyright(c) https://kodehelp.com All Rights Reserved.
*/
package com.kodehelp.sftp;
import java.io.File;
import java.util.Vector;
import com.jcraft.jsch.Channel;
import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;
import com.jcraft.jsch.SftpException;
/**
* @author https://kodehelp.com
*
*/
public class DownloadRecursiveFolderFromSFTP {
static ChannelSftp channelSftp = null;
static Session session = null;
static Channel channel = null;
static String PATHSEPARATOR = "/";
/**
* @param args
*/
public static void main(String[] args) {
String SFTPHOST = "10.20.30.40"; // SFTP Host Name or SFTP Host IP Address
int SFTPPORT = 22; // SFTP Port Number
String SFTPUSER = "SFTPUserName"; // User Name
String SFTPPASS = "SFTPPassword"; // Password
String SFTPWORKINGDIR = "/home/kodehelp/download"; // Source Directory on SFTP server
String LOCALDIRECTORY = "C:\\temp"; // Local Target Directory
try {
JSch jsch = new JSch();
session = jsch.getSession(SFTPUSER, SFTPHOST, SFTPPORT);
session.setPassword(SFTPPASS);
java.util.Properties config = new java.util.Properties();
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.connect(); // Create SFTP Session
channel = session.openChannel("sftp"); // Open SFTP Channel
channel.connect();
channelSftp = (ChannelSftp) channel;
channelSftp.cd(SFTPWORKINGDIR); // Change Directory on SFTP Server
// Recursive folder content download from SFTP server
recursiveFolderDownload(SFTPWORKINGDIR, LOCALDIRECTORY);
} catch (Exception ex) {
ex.printStackTrace();
} finally {
if (channelSftp != null)
channelSftp.disconnect();
if (channel != null)
channel.disconnect();
if (session != null)
session.disconnect();
}
}
/**
* This method is called recursively to download the folder content from SFTP
* server
*
* @param sourcePath
* @param destinationPath
* @throws SftpException
*/
@SuppressWarnings("unchecked")
private static void recursiveFolderDownload(String sourcePath, String destinationPath) throws SftpException {
Vector<ChannelSftp.LsEntry> fileAndFolderList = channelSftp.ls(sourcePath); // Let list of folder content
// Iterate through list of folder content
for (ChannelSftp.LsEntry item : fileAndFolderList) {
if (!item.getAttrs().isDir()) { // Check if it is a file (not a directory).
if (!(new File(destinationPath + PATHSEPARATOR + item.getFilename())).exists()
|| (item.getAttrs().getMTime() > Long
.valueOf(new File(destinationPath + PATHSEPARATOR + item.getFilename()).lastModified()
/ (long) 1000)
.intValue())) { // Download only if changed later.
new File(destinationPath + PATHSEPARATOR + item.getFilename());
// Download file from source (sourcefilename, destination filename).
channelSftp.get(sourcePath + PATHSEPARATOR + item.getFilename(),
destinationPath + PATHSEPARATOR + item.getFilename());
}
} else if (!(".".equals(item.getFilename()) || "..".equals(item.getFilename()))) {
new File(destinationPath + PATHSEPARATOR + item.getFilename()).mkdirs(); // Empty folder copy.
// Enter found folder on server to read its contents and create locally.
recursiveFolderDownload(sourcePath + PATHSEPARATOR + item.getFilename(),
destinationPath + PATHSEPARATOR + item.getFilename());
}
}
}
}