How to retrieve a file from a server via SFTP

Question

I m trying to retrieve a file from a server using SFTP  as opposed to FTPS  using Java  How can I do this

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Here is the complete source code of an example using JSch without having to worry about the ssh key checking   import com jcraft jsch     public class TestJSch       public static void main String args              JSch jsch   new JSch            Session session   null          try               session   jsch getSession  username    127 0 0 1   22               session setConfig  StrictHostKeyChecking    no                session setPassword  password                session connect                 Channel channel   session openChannel  sftp                channel connect                ChannelSftp sftpChannel    ChannelSftp  channel              sftpChannel get  remotefile txt    localfile txt                sftpChannel exit                session disconnect              catch  JSchException e                e printStackTrace                catch  SftpException e                e printStackTrace

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JSch library is the powerful library that can be used to read file from SFTP server  Below is the tested code to read file from SFTP location line by line  JSch jsch   new JSch            Session session   null          try               session   jsch getSession  user    127 0 0 1   22               session setConfig  StrictHostKeyChecking    no                session setPassword  password                session connect                 Channel channel   session openChannel  sftp                channel connect                ChannelSftp sftpChannel    ChannelSftp  channel               InputStream stream   sftpChannel get   usr home testfile txt                try                   BufferedReader br   new BufferedReader new InputStreamReader stream                    String line                  while   line   br readLine       null                        System out println line                                    catch  IOException io                    System out println  Exception occurred during reading file from SFTP server due to     io getMessage                     io getMessage                   catch  Exception e                    System out println  Exception occurred during reading file from SFTP server due to     e getMessage                     e getMessage                                sftpChannel exit                session disconnect              catch  JSchException e                e printStackTrace              catch  SftpException e                e printStackTrace                Please refer the blog for whole program

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Below is an example using Apache Common VFS   FileSystemOptions fsOptions   new FileSystemOptions    SftpFileSystemConfigBuilder getInstance   setStrictHostKeyChecking fsOptions   no    FileSystemManager fsManager   VFS getManager    String uri    sftp   user password host port absolute-path   FileObject fo   fsManager resolveFile uri  fsOptions

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This was the solution I came up with http   sourceforge net projects sshtools   most error handling omitted for clarity   This is an excerpt from my blog  SshClient ssh   new SshClient    ssh connect host  port     Authenticate PasswordAuthenticationClient passwordAuthenticationClient   new PasswordAuthenticationClient    passwordAuthenticationClient setUsername userName   passwordAuthenticationClient setPassword password   int result   ssh authenticate passwordAuthenticationClient   if result    AuthenticationProtocolState COMPLETE        throw new SFTPException  Login to     host         port         userName         password     failed        Open the SFTP channel SftpClient client   ssh openSftpClient      Send the file client put filePath     disconnect client quit    ssh disconnect

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Try edtFTPj PRO  a mature  robust SFTP client library that supports connection pools and asynchronous operations  Also supports FTP and FTPS so all bases for secure file transfer are covered

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A nice abstraction on top of Jsch is Apache commons-vfs which offers a virtual filesystem API that makes accessing and writing SFTP files almost transparent  Worked well for us

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hierynomus sshj has a complete implementation of SFTP version 3  what OpenSSH implements   Example code from SFTPUpload java  package net schmizz sshj examples   import net schmizz sshj SSHClient  import net schmizz sshj sftp SFTPClient  import net schmizz sshj xfer FileSystemFile   import java io File  import java io IOException       This example demonstrates uploading of a file over SFTP to the SSH server     public class SFTPUpload        public static void main String   args              throws IOException           final SSHClient ssh   new SSHClient            ssh loadKnownHosts            ssh connect  localhost            try               ssh authPublickey System getProperty  user name                 final String src   System getProperty  user home     File separator    test file               final SFTPClient sftp   ssh newSFTPClient                try                   sftp put new FileSystemFile src     tmp                  finally                   sftp close                            finally               ssh disconnect

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I use this SFTP API called Zehon  it s great  so easy to use with a lot of sample code  Here is the site http   www zehon com

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There is a nice comparison of the 3 mature Java libraries for SFTP  Commons VFS  SSHJ and JSch   To sum up SSHJ has the clearest API and it s the best out of them if you don t need other storages support provided by Commons VFS   Here is edited SSHJ example from github   final SSHClient ssh   new SSHClient    ssh loadKnownHosts       or  to skip host verification  ssh addHostKeyVerifier new PromiscuousVerifier    ssh connect  localhost    try       ssh authPassword  user    password       or ssh authPublickey System getProperty  user name        final SFTPClient sftp   ssh newSFTPClient        try           sftp get  test file     tmp test tmp          finally           sftp close            finally       ssh disconnect

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Apache Commons SFTP library   Common java properties file for all the examples  serverAddress 111 222 333 444  userId myUserId  password myPassword  remoteDirectory products      localDirectory import      Upload file to remote server using SFTP   import java io File  import java io FileInputStream  import java util Properties   import org apache commons vfs2 FileObject  import org apache commons vfs2 FileSystemOptions  import org apache commons vfs2 Selectors  import org apache commons vfs2 impl StandardFileSystemManager  import org apache commons vfs2 provider sftp SftpFileSystemConfigBuilder   public class SendMyFiles     static Properties props    public static void main String   args       SendMyFiles sendMyFiles   new SendMyFiles      if  args length  lt  1         System err println  Usage  java     sendMyFiles getClass   getName           Properties file File To FTP        System exit 1          String propertiesFile   args 0  trim      String fileToFTP   args 1  trim      sendMyFiles startFTP propertiesFile  fileToFTP         public boolean startFTP String propertiesFilename  String fileToFTP      props   new Properties      StandardFileSystemManager manager   new StandardFileSystemManager       try       props load new FileInputStream  properties     propertiesFilename       String serverAddress   props getProperty  serverAddress   trim       String userId   props getProperty  userId   trim       String password   props getProperty  password   trim       String remoteDirectory   props getProperty  remoteDirectory   trim       String localDirectory   props getProperty  localDirectory   trim          check if the file exists    String filepath   localDirectory    fileToFTP     File file   new File filepath      if   file exists        throw new RuntimeException  Error  Local file not found          Initializes the file manager    manager init          Setup our SFTP configuration    FileSystemOptions opts   new FileSystemOptions       SftpFileSystemConfigBuilder getInstance   setStrictHostKeyChecking       opts   no       SftpFileSystemConfigBuilder getInstance   setUserDirIsRoot opts  true      SftpFileSystemConfigBuilder getInstance   setTimeout opts  10000         Create the SFTP URI using the host name  userid  password   remote path and file name    String sftpUri    sftp       userId         password          serverAddress               remoteDirectory   fileToFTP         Create local file object    FileObject localFile   manager resolveFile file getAbsolutePath            Create remote file object    FileObject remoteFile   manager resolveFile sftpUri  opts          Copy local file to sftp server    remoteFile copyFrom localFile  Selectors SELECT SELF      System out println  File upload successful           catch  Exception ex       ex printStackTrace       return false        finally      manager close           return true              Download file from remote server using SFTP   import java io File  import java io FileInputStream  import java util Properties   import org apache commons vfs2 FileObject  import org apache commons vfs2 FileSystemOptions  import org apache commons vfs2 Selectors  import org apache commons vfs2 impl StandardFileSystemManager  import org apache commons vfs2 provider sftp SftpFileSystemConfigBuilder   public class GetMyFiles     static Properties props    public static void main String   args       GetMyFiles getMyFiles   new GetMyFiles      if  args length  lt  1         System err println  Usage  java     getMyFiles getClass   getName         Properties filename File To Download        System exit 1          String propertiesFilename   args 0  trim      String fileToDownload   args 1  trim      getMyFiles startFTP propertiesFilename  fileToDownload         public boolean startFTP String propertiesFilename  String fileToDownload      props   new Properties      StandardFileSystemManager manager   new StandardFileSystemManager       try       props load new FileInputStream  properties     propertiesFilename       String serverAddress   props getProperty  serverAddress   trim       String userId   props getProperty  userId   trim       String password   props getProperty  password   trim       String remoteDirectory   props getProperty  remoteDirectory   trim       String localDirectory   props getProperty  localDirectory   trim           Initializes the file manager    manager init          Setup our SFTP configuration    FileSystemOptions opts   new FileSystemOptions       SftpFileSystemConfigBuilder getInstance   setStrictHostKeyChecking       opts   no       SftpFileSystemConfigBuilder getInstance   setUserDirIsRoot opts  true      SftpFileSystemConfigBuilder getInstance   setTimeout opts  10000         Create the SFTP URI using the host name  userid  password   remote path and file name    String sftpUri    sftp       userId         password          serverAddress               remoteDirectory   fileToDownload         Create local file object    String filepath   localDirectory    fileToDownload     File file   new File filepath      FileObject localFile   manager resolveFile file getAbsolutePath            Create remote file object    FileObject remoteFile   manager resolveFile sftpUri  opts          Copy local file to sftp server    localFile copyFrom remoteFile  Selectors SELECT SELF      System out println  File download successful           catch  Exception ex       ex printStackTrace       return false        finally      manager close           return true             Delete a file on remote server using SFTP   import java io FileInputStream  import java util Properties   import org apache commons vfs2 FileObject  import org apache commons vfs2 FileSystemOptions  import org apache commons vfs2 impl StandardFileSystemManager  import org apache commons vfs2 provider sftp SftpFileSystemConfigBuilder   public class DeleteRemoteFile     static Properties props    public static void main String   args       DeleteRemoteFile getMyFiles   new DeleteRemoteFile      if  args length  lt  1         System err println  Usage  java     getMyFiles getClass   getName         Properties filename File To Delete        System exit 1          String propertiesFilename   args 0  trim      String fileToDownload   args 1  trim      getMyFiles startFTP propertiesFilename  fileToDownload         public boolean startFTP String propertiesFilename  String fileToDownload      props   new Properties      StandardFileSystemManager manager   new StandardFileSystemManager       try       props load new FileInputStream  properties     propertiesFilename       String serverAddress   props getProperty  serverAddress   trim       String userId   props getProperty  userId   trim       String password   props getProperty  password   trim       String remoteDirectory   props getProperty  remoteDirectory   trim           Initializes the file manager    manager init          Setup our SFTP configuration    FileSystemOptions opts   new FileSystemOptions       SftpFileSystemConfigBuilder getInstance   setStrictHostKeyChecking       opts   no       SftpFileSystemConfigBuilder getInstance   setUserDirIsRoot opts  true      SftpFileSystemConfigBuilder getInstance   setTimeout opts  10000         Create the SFTP URI using the host name  userid  password   remote path and file name    String sftpUri    sftp       userId         password          serverAddress               remoteDirectory   fileToDownload        Create remote file object    FileObject remoteFile   manager resolveFile sftpUri  opts         Check if the file exists    if remoteFile exists         remoteFile delete        System out println  File delete successful                catch  Exception ex       ex printStackTrace       return false        finally      manager close           return true

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I found complete working example for SFTP in java using JSCH API  http   kodehelp com java-program-for-uploading-file-to-sftp-server

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Though answers above were very helpful  I ve spent a day to make them work  facing various exceptions like  broken channel    rsa key unknown  and  packet corrupt    Below is a working reusable class for SFTP FILES UPLOAD DOWNLOAD using JSch library   Upload usage   SFTPFileCopy upload   new SFTPFileCopy true   path to sourcefile png    path to destinationfile png      Download usage   SFTPFileCopy download   new SFTPFileCopy false    path to sourcefile png     path to destinationfile png      The class code   import com jcraft jsch Channel  import com jcraft jsch ChannelSftp  import com jcraft jsch JSch  import com jcraft jsch Session  import com jcraft jsch UIKeyboardInteractive  import com jcraft jsch UserInfo  import java io BufferedInputStream  import java io BufferedOutputStream  import java io ByteArrayInputStream  import java io File  import java io FileInputStream  import java io FileNotFoundException  import java io FileOutputStream  import java io IOException  import java io OutputStream  import javax swing JOptionPane  import menue Menue   public class SFTPFileCopy1        public SFTPFileCopy1 boolean upload  String sourcePath  String destPath  throws FileNotFoundException  IOException           Session session   null          Channel channel   null          ChannelSftp sftpChannel   null          try               JSch jsch   new JSch                  jsch setKnownHosts   home user  putty sshhostkeys                session   jsch getSession  login    mysite com   22               session setPassword  password                 UserInfo ui   new MyUserInfo                     public void showMessage String message                         JOptionPane showMessageDialog null  message                                       public boolean promptYesNo String message                         Object   options     yes    no                         int foo   JOptionPane showOptionDialog null                              message                               Warning                               JOptionPane DEFAULT OPTION                              JOptionPane WARNING MESSAGE                              null  options  options 0                         return foo    0                                                session setUserInfo ui                session setConfig  StrictHostKeyChecking    no                session connect                channel   session openChannel  sftp                channel setInputStream System in               channel setOutputStream System out               channel connect                sftpChannel    ChannelSftp  channel               if  upload       File upload                  byte   bufr   new byte  int  new File sourcePath  length                     FileInputStream fis   new FileInputStream new File sourcePath                    fis read bufr                   ByteArrayInputStream fileStream   new ByteArrayInputStream bufr                   sftpChannel put fileStream  destPath                   fileStream close                  else      File download                  byte   buffer   new byte 1024                   BufferedInputStream bis   new BufferedInputStream sftpChannel get sourcePath                    OutputStream os   new FileOutputStream new File destPath                    BufferedOutputStream bos   new BufferedOutputStream os                   int readCount                  while   readCount   bis read buffer    gt  0                        bos write buffer  0  readCount                                     bis close                    bos close                            catch  Exception e                System out println e             finally               if  sftpChannel    null                    sftpChannel exit                              if  channel    null                    channel disconnect                              if  session    null                    session disconnect                                       public static abstract class MyUserInfo             implements UserInfo  UIKeyboardInteractive            public String getPassword                 return null                     public boolean promptYesNo String str                return false                     public String getPassphrase                 return null                     public boolean promptPassphrase String message                return false                     public boolean promptPassword String message                return false                     public void showMessage String message                       public String   promptKeyboardInteractive String destination                  String name                  String instruction                  String   prompt                  boolean   echo                 return null

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Another option is to consider looking at the JSch library  JSch seems to be the preferred library for a few large open source projects  including Eclipse  Ant and Apache Commons HttpClient  amongst others   It supports both user pass and certificate-based logins nicely  as well as all a whole host  of other yummy SSH2 features   Here s a simple remote file retrieve over SFTP  Error handling is left as an exercise for the reader  -   JSch jsch   new JSch     String knownHostsFilename     home username  ssh known hosts   jsch setKnownHosts  knownHostsFilename     Session session   jsch getSession   remote-username    remote-host                 interactive  version      can selectively update specified known hosts file       need to implement UserInfo interface      MyUserInfo is a swing implementation provided in        examples Sftp java in the JSch dist   UserInfo ui   new MyUserInfo      session setUserInfo ui         OR non-interactive version  Relies in host key being in known-hosts file   session setPassword   remote-password        session connect     Channel channel   session openChannel   sftp     channel connect     ChannelSftp sftpChannel    ChannelSftp  channel   sftpChannel get  remote-file    local-file        OR InputStream in   sftpChannel get   remote-file          process inputstream as needed  sftpChannel exit    session disconnect

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Andy  to delete file on remote system you need to use  channelExec  of JSch and pass unix linux commands to delete it

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You also have JFileUpload with SFTP add-on  Java too   http   www jfileupload com products sftp index html

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The best solution I ve found is Paramiko  There s a Java version

[java] How to retrieve a file from a server via SFTP?

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