[RESOLVED] Retrieve files from remote machine

[shik28]

Hi,
I have written the following code to establish connection to the remote unix machine which works fine. How do I retrieve a particular file from that system?

package my.userauthki;

import com.jcraft.jsch.*;
import java.awt.*;
import javax.swing.*;

public class UserAuthKI {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		try{
		      JSch jsch=new JSch();

		      String host=null;
		      if(args.length>0){
		        host=args[0];
		      }
		      else{
		        host=JOptionPane.showInputDialog("Enter username@hostname",
		                                         System.getProperty("user.name")+
		                                         "@localhost"); 
		      }
		      String user=host.substring(0, host.indexOf('@'));
		      host=host.substring(host.indexOf('@')+1);

		      Session session=jsch.getSession(user, host, 22);

		      // username and passphrase will be given via UserInfo interface.
		      UserInfo ui=new MyUserInfo();
		      session.setUserInfo(ui);
		      session.connect();

		      Channel channel=session.openChannel("shell");

		      channel.setInputStream(System.in);
		      channel.setOutputStream(System.out);

		      channel.connect();
		    }
		    catch(Exception e){
		      System.out.println(e);
		    }
		  }

		  public static class MyUserInfo implements UserInfo, UIKeyboardInteractive{
		    public String getPassword(){ return passwd; }
		    public boolean promptYesNo(String str){
		      Object[] options={ "yes", "no" };
		      int foo=JOptionPane.showOptionDialog(null, 
		             str,
		             "Warning", 
		             JOptionPane.DEFAULT_OPTION, 
		             JOptionPane.WARNING_MESSAGE,
		             null, options, options[0]);
		       return foo==0;
		    }

		    String passwd;
		    JTextField passwordField=(JTextField)new JPasswordField(20);
		  
		    public String getPassphrase(){ return null; }
		    public boolean promptPassphrase(String message){ return false; }
		    public boolean promptPassword(String message){
		      Object[] ob={passwordField}; 
		      int result=
		        JOptionPane.showConfirmDialog(null, ob, message,
		                                      JOptionPane.OK_CANCEL_OPTION);
		      if(result==JOptionPane.OK_OPTION){
		        passwd=passwordField.getText();
		        return true;
		      }
		      else{ 
		        return false; 
		      }
		    }
		    public void showMessage(String message){
		      JOptionPane.showMessageDialog(null, message);
		    }

		    final GridBagConstraints gbc = 
		      new GridBagConstraints(0,0,1,1,1,1,
		                             GridBagConstraints.NORTHWEST,
		                             GridBagConstraints.NONE,
		                             new Insets(0,0,0,0),0,0);
		    private Container panel;
		    public String[] promptKeyboardInteractive(String destination,
		                                              String name,
		                                              String instruction,
		                                              String[] prompt,
		                                              boolean[] echo){
		/*
		//System.out.println("promptKeyboardInteractive");
		System.out.println("destination: "+destination);
		System.out.println("name: "+name);
		System.out.println("instruction: "+instruction);
		System.out.println("prompt.length: "+prompt.length);
		System.out.println("prompt: "+prompt[0]);
		*/
		      panel = new JPanel();
		      panel.setLayout(new GridBagLayout());

		      gbc.weightx = 1.0;
		      gbc.gridwidth = GridBagConstraints.REMAINDER;
		      gbc.gridx = 0;
		      panel.add(new JLabel(instruction), gbc);
		      gbc.gridy++;

		      gbc.gridwidth = GridBagConstraints.RELATIVE;

		      JTextField[] texts=new JTextField[prompt.length];
		      for(int i=0; i<prompt.length; i++){
		        gbc.fill = GridBagConstraints.NONE;
		        gbc.gridx = 0;
		        gbc.weightx = 1;
		        panel.add(new JLabel(prompt[i]),gbc);

		        gbc.gridx = 1;
		        gbc.fill = GridBagConstraints.HORIZONTAL;
		        gbc.weighty = 1;
		        if(echo[i]){
		          texts[i]=new JTextField(20);
		        }
		        else{
		          texts[i]=new JPasswordField(20);
		        }
		        panel.add(texts[i], gbc);
		        gbc.gridy++;
		      }

		      if(JOptionPane.showConfirmDialog(null, panel, 
		                                       destination+": "+name,
		                                       JOptionPane.OK_CANCEL_OPTION,
		                                       JOptionPane.QUESTION_MESSAGE)
		         ==JOptionPane.OK_OPTION){
		        String[] response=new String[prompt.length];
		        for(int i=0; i<prompt.length; i++){
		          response[i]=texts[i].getText();
		        }
			return response;
		      }
		      else{
		        return null;  // cancel
		      }
		    }

	}

}

[aamir121a]

and the protocol you are using to connect FTP SSH , ??? try not to put everything inside the main method ( makes bad programming practice)

[shik28]

Yes @aamir121a it's ssh. Got to optimize the code.

[aamir121a]

then that easy , SSH will give you remote shell , all you have to do then is SFTP ( part of SSH ) or use commands like cd and cp to navigate through files

[shik28]

Yeah ok I will try with SFTP. But when I try to open any file in the shell with the vi command, some files appear to contain lot of other junk data apart from what is actually present.

Moreover, I want to develop an application where the user can enter the filename in the GUI itself which will make a copy of that file from the remote system to my local system.

[keang]

Got to optimize the code.

Premature optimization is the root of all evil - Donald Knuth.

Never sacrifice good design principles for optimization until you know you definitely have a performance issue and you know exactly where that performance issue is. And the only way you can know where you have an issue is to have written the code and performed analysis on the code.

BTW from years of experience I can tell you that, almost certainly, the bit of code you think you need to optimize won't in fact be the bit of code that is causing a problem. And more often than not, a timely feedback to the user is way more important to the user than having the application take a few less milliseconds.

[aamir121a]

that's easy too , user input in GUI be validated Look at the end of the day I can't teach you everything Java , to try to put your questions in way that they can be answered short and simple , for the rest you dot to do your research cheers

[shik28]

@keang: Agree with you.

@aamir121a: thanks.