Downloading files from an SFTP server using JSch

I fixed in this way:

Vector<ChannelSftp.LsEntry> files = sftp.ls(remotePath);
String remotePath = properties.getFtpPath();
Vector<ChannelSftp.LsEntry> files = sftp.ls(remotePath);

for (ChannelSftp.LsEntry entry : files) {

    InputStream stream = sftp.get(remotePath + "/" + entry.getFilename());
    // Your business code here

}

Where remotePath is the remote SFTP folder name.


Please find in the below code sample comprising the file upload and download functionalities. Please pull the relevant details from properties files where ever string marked in lt;sftp.user.namegt;. I am deleting the file once the file is downloaded you can have it as per your requirement.

The event and locale parameters what I have added as part of download functionality is to filter the file(s); you can pass parameters as par you need.

Have placed a check to set proxy which can be used on need basis.

package com.util;

import com.jcraft.jsch.Channel;
import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.ProxyHTTP;
import com.jcraft.jsch.Session;
import com.jcraft.jsch.SftpException;
import java.io.File;
import java.io.FileInputStream;
import java.util.Date;
import java.util.Properties;
import java.util.Vector;

/**
 *
 * @author Dinesh.Lomte
 */
public class SftpUtil {

    /**
     * 
     * @param fileName
     * @throws Exception 
     */
    public static void upload(String fileName)
    throws Exception {

        String method = "upload(String fileName)";
        Session session = null;
        Channel channel = null;
        ChannelSftp channelSftp = null;
        try {
            // Creating and instantiating the jsch specific instance
            JSch jsch = new JSch();
            // Fetching and setting the parameters like: user name, host and port 
            // from the properties file
            session = jsch.getSession("<sftp.user.name>",
                    "<sftp.host>",
                    Integer.valueOf("<sftp.port>"));
            // Fetching and setting the password as configured in properties files
            session.setPassword("<sftp.user.password>");
            // Setting the configuration specific properties
            Properties config = new Properties();
            config.put("StrictHostKeyChecking", "no");
            session.setConfig(config);            
            // Validating if proxy is enabled to access the sftp
            isSftpProxyEnabled(session);
            // Execution start time
            long lStartTime = new Date().getTime();
            System.out.println("Connecting to the sftp...");
            // Connecting to the sftp 
            session.connect();
            System.out.println("Connected to the sftp.");            
            // Execution end time
            long lEndTime = new Date().getTime();
            System.out.println("---------------------------------------------");
            System.out.println("Connected to SFTP in : " + (lEndTime - lStartTime));
            // Setting the channel type as sftp
            channel = session.openChannel("sftp");
            // Establishing the connection
            channel.connect();
            channelSftp = (ChannelSftp) channel;
            // Setting the folder location of the external system as configured
            channelSftp.cd("<sftp.output.folder.url>");
            // Creating the file instance
            File file = new File(fileName);
            // Creating an fileInputStream instance
            FileInputStream fileInputStream = new FileInputStream(file);
            // Transfering the file from it source to destination location via sftp
            channelSftp.put(fileInputStream, file.getName());
            // Closing the fileInputStream instance
            fileInputStream.close();
            // De-allocating the fileInputStream instance memory by assigning null
            fileInputStream = null;
        } catch (Exception exception) {
            throw exception;
        } finally {
            // Validating if channel sftp is not null to exit
            if (channelSftp != null) {
                channelSftp.exit();
            }
            // Validating if channel is not null to disconnect
            if (channel != null) {
                channel.disconnect();
            }
            // Validating if session instance is not null to disconnect
            if (session != null) {
                session.disconnect();
            }
        }
    }

    /**
     * 
     * @param session 
     */
    private static void isSftpProxyEnabled(Session session) {
        // Fetching the sftp proxy flag set as part of the properties file
        boolean isSftpProxyEnabled = Boolean.valueOf("<sftp.proxy.enable>");
        // Validating if proxy is enabled to access the sftp
        if (isSftpProxyEnabled) {
            // Setting host and port of the proxy to access the SFTP
            session.setProxy(new ProxyHTTP("<sftp.proxy.host>", 
                    Integer.valueOf("<sftp.proxy.port>");
        }
        System.out.println("Proxy status: " + isSftpProxyEnabled);
    }

    /**
     * 
     * @param folder
     * @param event
     * @param locale
     */
    public static void download(String folder, String event, String locale) {

        String method = "download(String folder, String event, String locale)";
        Session session = null;
        Channel channel = null;
        ChannelSftp channelSftp = null;
        try {
            // Creating and instantiating the jsch specific instance
            JSch jsch = new JSch();
            // Fetching and setting the parameters like: user name, host and port 
            // from the properties file
            session = jsch.getSession("<sftp.user.name>",
                    "<sftp.host>",
                    Integer.valueOf("<sftp.port>"));
            // Fetching and setting the password as configured in properties files
            session.setPassword("<sftp.user.password>");
            // Setting the configuration specific properties
            Properties config = new Properties();
            config.put("StrictHostKeyChecking", "no");
            session.setConfig(config);            
            // Validating if proxy is enabled to access the sftp
            isSftpProxyEnabled(session);
            // Execution start time
            long lStartTime = new Date().getTime();
            System.out.println("Connecting to the sftp...");
            // Connecting to the sftp 
            session.connect();
            System.out.println("Connected to the sftp.");            
            // Execution end time
            long lEndTime = new Date().getTime();
            System.out.println("---------------------------------------------");
            System.out.println("Connected to SFTP in : " + (lEndTime - lStartTime));
            // Setting the channel type as sftp
            channel = session.openChannel(SFTP);
            // Establishing the connection
            channel.connect();
            channelSftp = (ChannelSftp) channel;
            try {
                // Setting the folder location of the external system as configured 
                // to download the file from
                channelSftp.cd("<sftp.input.folder.url>");
            } catch (SftpException sftpException) {
                System.out.println("Failed to change the directory in sftp.");                
            }
            // Listing all the .csv file(s) specific to the source system, event type (download) and locale code
            Vector<ChannelSftp.LsEntry> lsEntries = channelSftp.ls(
                    new StringBuilder("*").append("<sys.code>").append("*").append(event)
                    .append("*").append(locale).append("*").append(".csv").toString());
            // Validating if files exist to process the request further
            if (lsEntries.isEmpty()) {
                System.out.println("No file exist in the specified sftp folder location.");
            }
            // Iterating the list of entries to download the file(s) from the sftp 
            for (ChannelSftp.LsEntry entry : lsEntries) {
                try {
                    // Downloading the specified file from the sftp to the specified folder path
                    channelSftp.get(entry.getFilename(), new StringBuilder(folder)
                            .append(File.separator).append(entry.getFilename()).toString());
                } catch (SftpException sftpException) {
                    System.out.println("Failed to download the file the sftp folder location.");                    
                }                
            }
            // Iterating the list of entries to delete the file(s) from the sftp 
            for (ChannelSftp.LsEntry entry : lsEntries) {
                try {
                    // Deleting the specified file from the sftp
                    channelSftp.rm(entry.getFilename());
                } catch (SftpException sftpException) {
                    System.out.println("Failed to delete the file from the sftp folder location.");                    
                }                
            }
        } catch (Exception exception) {
            System.out.println("Failed to download the file(s) from SFTP.");            
        } finally {
            // Validating if channel sftp is not null to exit
            if (channelSftp != null) {
                channelSftp.exit();
            }
            // Validating if channel is not null to disconnect
            if (channel != null) {
                channel.disconnect();
            }
            // Validating if session instance is not null to disconnect
            if (session != null) {
                session.disconnect();
            }
        }
    }
}

Try using paths instead of stream:

String destPath = "filename.txt";        

if (!filesToDownload.isEmpty()) {
    for (String fileDownloadName : filesToDownload) {
        success = false;
        sftpChannel.get(fileDownloadName , destPath);  

If you wanna use file and streams check this example:
http://kodehelp.com/java-program-for-downloading-file-from-sftp-server/

Tags:

Java

Sftp

Jsch