从Java程序写入终端

Question

I wanted to write a java programm that open some terminals which executes in each terminal "cd go/to/a/specitic/folder". (I don't want to execute a batch/script/shell file.)

It would be great if these could be plattform independent. Currently I´m working with a mac.

I searched the web for the hole weekend and do x tries with netbeans, but there wasn't a positive result. One close try, I found was here http://www.coderanch.com/t/532229/java/java/Writing-terminal-Java-program .

The best codes I tried were:

public class NewClass1 {

public static void main(String[] args) {

    try {
        Desktop.getDesktop().open(new File("/Applications/Utilities/Terminal.app"));
    } catch (IOException ex) {
        Logger.getLogger(StartDevelop.class.getName()).log(Level.SEVERE, null, ex);
    }
    // opens a terminal but no comments / parameters could be used   
}    
}

an other try was by changing all code in the main section through:

    ProcessBuilder builder = new ProcessBuilder( 
            "/Applications/Utilities/Terminal.app/Contents/MacOS/Terminal");
    builder.redirectErrorStream(true);

    try {
        String command = "ls -lai";
        Process process = builder.start();

        BufferedReader read = new BufferedReader(new InputStreamReader(
                process.getInputStream()));
        String s;

        while ((s = read.readLine()) != null) {
            System.out.println(s);
        }
    } catch (Exception e1) {
        // TODO Auto-generated catch block
        System.out.println(e1);
    }
    //open a terminal but command is executed in terminal

and an other alternative:

    try {
        String command = "ls -lai";
        Process process = Runtime.getRuntime().exec(command);
        BufferedReader read = new BufferedReader(new InputStreamReader(process.getInputStream()));
        String s;
        while ((s = read.readLine()) != null) {
            System.out.println(s);
        }
    } catch (IOException e1) {
        // TODO Auto-generated catch block
        System.out.println(e1);
    }
    // works with output in netbeans
    // but no terminal is opening

I tried also to use an Outputwriter:

 BufferedWriter outWrite = new BufferedWriter(
                new OutputStreamWriter(process.getOutputStream(), command));

 outWrite.flush();
 outWrite.newLine();

but with no effect.

Thanks in advance.

Answer 1

Cupido,

you need "SSH for Java".

Give a try Ganymed SSH-2 for Java

It provides even more than you need.

Here is a list of other Java SSH libraries
http://linuxmafia.com/ssh/java.html.

I would suggest the Ganymed SSH because it's widely used and under BSD licence (you don't have to open-source your code).

Perhaps you would want a better control over login/password information. It's a bad idea to hardcode logins and passwords in Java code for a two reasons:
- passwords shouldn't be stored in clear text (everyone who gets your program - gets access to your servers. Even compiled Java classes will contain clear strings for login and password. It isn't what you want)
- you don't want to change your Java program if passwords were changed

You can generate key pairs on hosts where you want to connect to, then exchange the keys. More about this here . As result, you will not be asked about login and passwords for hosts you configured.

Good luck.

Answer 2

If you don't need interactive access to the terminal window you could dynamically create a shell script and use xterm to run the script.

Example:

xterm -e path-to-script.sh

To keept the application open after execution use the -hold option.

Minimalistic example:

echo "echo hello;/bin/bash" > /tmp/tmp123.sh; chmod +x /tmp/tmp123.sh;xterm -hold -e /tmp/tmp123.sh

For completeness, this is how it could be done on Windows (replace echo hello with the commands you want to execute):

start cmd /C echo hello

To keep the window open after execution use the /K option instead of /C .

Answer 3

Short answer: you can't.

Long answer: the problem is, even if you successfully invoked your terminals, you'd need to know what the tty for each of these terminals in, which means you'd need to know what its stdin is... Provided that the OS doesn't do some strange mechanics which makes it so that the terminals don't even use file descriptors 0, 1 and 2 for stdin, stdout and stderr.

And even if you could do that, you'd need to be able to write to the tty anyway.