Using the Process.getOutputStream() method

Question

Hi all,
i have written a java program that executes System commands and returns output...
this program works fine if you want to only execute the command and returns output...
but suppose that the program that you executed waits for you to input something before returning ouput?!!
i suppose i have to use the Process.getOutputStraem() method in my prog!
but i don't know how to do that :-(
can any one help me to refine the prog to handle this case !
thanks a lot
here is the code:
import java.util.*;
import java.io.*;
class StreamGobbler extends Thread
    InputStream is;
    String type;
    OutputStream os;
    StreamGobbler(InputStream is, String type)
        this(is, type, null);
    StreamGobbler(InputStream is, String type, OutputStream redirect)
        this.is = is;
        this.type = type;
        this.os = redirect;
    public void run()
        try
            PrintWriter pw = null;
            if (os != null)
                pw = new PrintWriter(os);
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            String line=null;
            while ( (line = br.readLine()) != null)
                if (pw != null)
                    pw.println(line);
                System.out.println(type + ">" + line);   
            if (pw != null)
                pw.flush();
        } catch (IOException ioe)
            ioe.printStackTrace(); 
public class GoodWinRedirect
    public static void main(String args[])
        if (args.length < 1)
            System.out.println("USAGE java GoodWinRedirect <outputfile>");
            System.exit(1);
        try
            FileOutputStream fos = new FileOutputStream(args[0]);
            Runtime rt = Runtime.getRuntime();
            Process proc = rt.exec("java jecho 'Hello World'");
            // any error message?
            StreamGobbler errorGobbler = new
                StreamGobbler(proc.getErrorStream(), "ERROR");           
            // any output?
            StreamGobbler outputGobbler = new
                StreamGobbler(proc.getInputStream(), "OUTPUT", fos);
            // kick them off
            errorGobbler.start();
            outputGobbler.start();
            // any error???
            int exitVal = proc.waitFor();
            System.out.println("ExitValue: " + exitVal);
            fos.flush();
            fos.close();       
        } catch (Throwable t)
            t.printStackTrace();
}

Answer 1

it's true that i've copied it and pasted it...
but i do understand how it works (really)
the article mentioned at last that we could send input
to the Program by invoking getoutputStream
i guess that we should write a construtor for the
streamGobbler class but this time using a
OutputStreamReader and may be doing sth elseThe "Gobbler" is there to eat up whatever bytes become available on an InputStream (from the program's output). I don't think ou just want to try to use the same class to handle the program's input.
The Gobbler can be used for eating up whatever comes out of any program--it' general, and doesn't rely on any particular output from the program (input to the Gobler). This is not the case for whatever writes to the program's input. You'll need to write what the program expects in the proper order.