How to read console ouput

Question

Using the Grails framework how would one go about reading console output. What I mean is I have a java library in my grails app that outputs(system.out.println(\"x\")) to the co

Answer 1

You can redirect the output with the System.setOut() method. Here is a quick example that redirects System.out to a text pane after five seconds:

import javax.swing.*;
import java.awt.*;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.Date;

public class TextCapture {

    public static void main(String[] args) throws Exception {
        JFrame jf = new JFrame();
        jf.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        final JTextArea jta = new JTextArea();
        jta.setPreferredSize(new Dimension(400, 200));
        jf.getContentPane().add(jta);
        jf.pack();
        jf.setVisible(true);

        OutputStream textOS = new OutputStream() {
            @Override
            public void write(int b) throws IOException {
                jta.setText(jta.getText() + ((char)b));
            }
        };

        for(int i = 0; i < 20; i++) {
            Thread.sleep(1000);
            if(i == 5) {
                System.setOut(new PrintStream(textOS));
            }
            System.out.println(String.valueOf(new Date()));
        }
    }

}

Answer 2

We can use log4j configuration, write your app logs in a file, keep reading same file with your app. This should suffice your requirement. Read more on http://grails.org/doc/latest/guide/conf.html section 5.1.2 Logging