Créer une console Java à l'intérieur d'un panneau GUI

voici un cours fonctionnel. Vous pouvez installer une instance de ce type dans le système out et err en utilisant:

PrintStream con=new PrintStream(new TextAreaOutputStream(...));
System.setOut(con);
System.setErr(con);

mise à jour 2014-02-19: pour utiliser EventQueue.invokeLater() pour éviter les problèmes de filetage GUI qui peuvent apparaître très rarement avec l'original.

mise à jour 2014-02-27: meilleure mise en oeuvre

mise à jour 2014-03-25: Correction de l'enregistrement et de la suppression des lignes dans la zone de texte pour être dans le run() méthode de évitez les conditions de course entre l'ajout et la suppression qui peuvent se produire si la console est inondée de sortie. Le résultat final me semble aussi plus propre.

import java.awt.*;
import java.io.*;
import java.util.*;
import java.util.List;
import javax.swing.*;

public class TextAreaOutputStream
extends OutputStream
{

// *************************************************************************************************
// INSTANCE MEMBERS
// *************************************************************************************************

private byte[]                          oneByte;                                                    // array for write(int val);
private Appender                        appender;                                                   // most recent action

public TextAreaOutputStream(JTextArea txtara) {
    this(txtara,1000);
    }

public TextAreaOutputStream(JTextArea txtara, int maxlin) {
    if(maxlin<1) { throw new IllegalArgumentException("TextAreaOutputStream maximum lines must be positive (value="+maxlin+")"); }
    oneByte=new byte[1];
    appender=new Appender(txtara,maxlin);
    }

/** Clear the current console text area. */
public synchronized void clear() {
    if(appender!=null) { appender.clear(); }
    }

public synchronized void close() {
    appender=null;
    }

public synchronized void flush() {
    }

public synchronized void write(int val) {
    oneByte[0]=(byte)val;
    write(oneByte,0,1);
    }

public synchronized void write(byte[] ba) {
    write(ba,0,ba.length);
    }

public synchronized void write(byte[] ba,int str,int len) {
    if(appender!=null) { appender.append(bytesToString(ba,str,len)); }
    }

@edu.umd.cs.findbugs.annotations.SuppressWarnings("DM_DEFAULT_ENCODING")
static private String bytesToString(byte[] ba, int str, int len) {
    try { return new String(ba,str,len,"UTF-8"); } catch(UnsupportedEncodingException thr) { return new String(ba,str,len); } // all JVMs are required to support UTF-8
    }

// *************************************************************************************************
// STATIC MEMBERS
// *************************************************************************************************

    static class Appender
    implements Runnable
    {
    private final JTextArea             textArea;
    private final int                   maxLines;                                                   // maximum lines allowed in text area
    private final LinkedList<Integer>   lengths;                                                    // length of lines within text area
    private final List<String>          values;                                                     // values waiting to be appended

    private int                         curLength;                                                  // length of current line
    private boolean                     clear;
    private boolean                     queue;

    Appender(JTextArea txtara, int maxlin) {
        textArea =txtara;
        maxLines =maxlin;
        lengths  =new LinkedList<Integer>();
        values   =new ArrayList<String>();

        curLength=0;
        clear    =false;
        queue    =true;
        }

    synchronized void append(String val) {
        values.add(val);
        if(queue) { queue=false; EventQueue.invokeLater(this); }
        }

    synchronized void clear() {
        clear=true;
        curLength=0;
        lengths.clear();
        values.clear();
        if(queue) { queue=false; EventQueue.invokeLater(this); }
        }

    // MUST BE THE ONLY METHOD THAT TOUCHES textArea!
    public synchronized void run() {
        if(clear) { textArea.setText(""); }
        for(String val: values) {
            curLength+=val.length();
            if(val.endsWith(EOL1) || val.endsWith(EOL2)) {
                if(lengths.size()>=maxLines) { textArea.replaceRange("",0,lengths.removeFirst()); }
                lengths.addLast(curLength);
                curLength=0;
                }
            textArea.append(val);
            }
        values.clear();
        clear =false;
        queue =true;
        }

    static private final String         EOL1="\n";
    static private final String         EOL2=System.getProperty("line.separator",EOL1);
    }

} /* END PUBLIC CLASS */

Et voici une capture d'écran dans l'action:

@Logiciel De Singe:

ça marche! :)

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;

public class Main{
    public static void main( String [] args ) throws InterruptedException  {
        JFrame frame = new JFrame();
        frame.add( new JLabel(" Outout" ), BorderLayout.NORTH );

        JTextArea ta = new JTextArea();
        TextAreaOutputStream taos = new TextAreaOutputStream( ta, 60 );
        PrintStream ps = new PrintStream( taos );
        System.setOut( ps );
        System.setErr( ps );


        frame.add( new JScrollPane( ta )  );

        frame.pack();
        frame.setVisible( true );
        frame.setSize(800,600);

        for( int i = 0 ; i < 100 ; i++ ) {
            System.out.println( i );
            Thread.sleep( 500 );
        }
    }
}

je sais que c'est un vieux fil, mais le fait que je l'ai trouvé en essayant de trouver une bonne façon de le faire signifie que d'autres le feront probablement aussi.

Voici une façon (probablement) plus propre de faire ce que software monkey a posté:

import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;

import javax.swing.JTextArea;

/**
 * Represents a console viewable through a <code>JTextArea</code>.
 * 
 * <p>
 *  Implementation:
 *  <code>
 *      System.setOut(new PrintStream(new Console( ... )));
 *  </code>
 *  </p>
 * 
 * @author Derive McNeill
 *
 */
public class Console extends OutputStream {

    /**
     * Represents the data written to the stream.
     */
    ArrayList <Byte> data = new ArrayList <Byte> ();

    /**
     * Represents the text area that will be showing the written data.
     */
    private JTextArea output;

    /**
     * Creates a console context.
     * @param output
     *      The text area to output the consoles text.
     */
    public Console(JTextArea output) {
        this.output = output;
    }

    /**
     * Called when data has been written to the console.
     */
    private void fireDataWritten() {

        // First we loop through our written data counting the lines.
        int lines = 0;
        for (int i = 0; i < data.size(); i++) {
            byte b = data.get(i);

            // Specifically we look for 10 which represents "\n".
            if (b == 10) {
                lines++;
            }

            // If the line count exceeds 250 we remove older lines.
            if (lines >= 250) {
                data = (ArrayList<Byte>) data.subList(i, data.size());
            }
        }

        // We then create a string builder to append our text data.
        StringBuilder bldr = new StringBuilder();

        // We loop through the text data appending it to the string builder.
        for (byte b : data) {
            bldr.append((char) b);
        }

        // Finally we set the outputs text to our built string.
        output.setText(bldr.toString());
    }

    @Override
    public void write(int i) throws IOException {

        // Append the piece of data to our array of data.
        data.add((byte) i);

        // Indicate that data has just been written.
        fireDataWritten();
    }

}

ByteArrayOutputStream peut être utilisé pour omettre le tampon.

private void redirectConsoleTo(final JTextArea textarea) {
    PrintStream out = new PrintStream(new ByteArrayOutputStream() {
        public synchronized void flush() throws IOException {
            textarea.setText(toString());
        }
    }, true);

    System.setErr(out);
    System.setOut(out);
}

au lieu de limiter le nombre de lignes, vous pouvez lier ByteArrayOutputStream#reset () à un bouton.

private void redirectConsoleWithClearButton(final JTextArea textarea, JButton clearButton) {
    final ByteArrayOutputStream bytes = new ByteArrayOutputStream() {
        public synchronized void flush() throws IOException {
            textarea.setText(toString());
        }
    };

    clearButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            bytes.reset();
        }
    });

    PrintStream out = new PrintStream(bytes, true);

    System.setErr(out);
    System.setOut(out);
}

récemment, j'ai utiliser le excellent code fourni par Laurent Dol dans un de mes projet.

Cependant, dans mon cas, le code consommé trop de mémoire. J'ai réussi à réduire drastiquement la consommation de mémoire en remplaçant JTextarea par un JLabel.

Mes recherches de mémorisation ont montré que JTextarea code interne tend à maintenir le texte envoyé trop de temps. Par conséquent, tout ce texte ne pouvait pas être ramassé.

Ici est la version flexible du code initial (avec synchronisation de thread remplacée par des serrures).

JComponentOutputStream.java

import java.awt.EventQueue;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

import javax.swing.JComponent;

public class JComponentOutputStream extends OutputStream {

    // *************************************************************************************************
    // INSTANCE MEMBERS
    // *************************************************************************************************

    private byte[] oneByte; // array for write(int val);
    private Appender appender; // most recent action

    private Lock jcosLock = new ReentrantLock();

    public JComponentOutputStream(JComponent txtara, JComponentHandler handler) {
        this(txtara, 1000, handler);
    }

    public JComponentOutputStream(JComponent txtara, int maxlin, JComponentHandler handler) {
        if (maxlin < 1) {
            throw new IllegalArgumentException("JComponentOutputStream maximum lines must be positive (value=" + maxlin + ")");
        }
        oneByte = new byte[1];
        appender = new Appender(txtara, maxlin, handler);
    }

    /** Clear the current console text area. */
    public void clear() {
        jcosLock.lock();
        try {
            if (appender != null) {
                appender.clear();
            }
        } finally {
            jcosLock.unlock();
        }
    }

    public void close() {
        jcosLock.lock();
        try {
            appender = null;
        } finally {
            jcosLock.unlock();
        }
    }

    public void flush() {
        // sstosLock.lock();
        // try {
        // // TODO: Add necessary code here...
        // } finally {
        // sstosLock.unlock();
        // }
    }

    public void write(int val) {
        jcosLock.lock();
        try {
            oneByte[0] = (byte) val;
            write(oneByte, 0, 1);
        } finally {
            jcosLock.unlock();
        }
    }

    public void write(byte[] ba) {
        jcosLock.lock();
        try {
            write(ba, 0, ba.length);
        } finally {
            jcosLock.unlock();
        }
    }

    public void write(byte[] ba, int str, int len) {
        jcosLock.lock();
        try {
            if (appender != null) {
                appender.append(bytesToString(ba, str, len));
            }
        } finally {
            jcosLock.unlock();
        }
    }

    static private String bytesToString(byte[] ba, int str, int len) {
        try {
            return new String(ba, str, len, "UTF-8");
        } catch (UnsupportedEncodingException thr) {
            return new String(ba, str, len);
        } // all JVMs are required to support UTF-8
    }

    // *************************************************************************************************
    // STATIC MEMBERS
    // *************************************************************************************************

    static class Appender implements Runnable {
        private final JComponent swingComponent;
        private final int maxLines; // maximum lines allowed in text area
        private final LinkedList<Integer> lengths; // length of lines within
                                                    // text area
        private final List<String> values; // values waiting to be appended

        private int curLength; // length of current line
        private boolean clear;
        private boolean queue;

        private Lock appenderLock;

        private JComponentHandler handler;

        Appender(JComponent cpt, int maxlin, JComponentHandler hndlr) {
            appenderLock = new ReentrantLock();

            swingComponent = cpt;
            maxLines = maxlin;
            lengths = new LinkedList<Integer>();
            values = new ArrayList<String>();

            curLength = 0;
            clear = false;
            queue = true;

            handler = hndlr;
        }

        void append(String val) {
            appenderLock.lock();
            try {
                values.add(val);
                if (queue) {
                    queue = false;
                    EventQueue.invokeLater(this);
                }
            } finally {
                appenderLock.unlock();
            }
        }

        void clear() {
            appenderLock.lock();
            try {

                clear = true;
                curLength = 0;
                lengths.clear();
                values.clear();
                if (queue) {
                    queue = false;
                    EventQueue.invokeLater(this);
                }
            } finally {
                appenderLock.unlock();
            }
        }

        // MUST BE THE ONLY METHOD THAT TOUCHES the JComponent!
        public void run() {
            appenderLock.lock();
            try {
                if (clear) {
                    handler.setText(swingComponent, "");
                }
                for (String val : values) {
                    curLength += val.length();
                    if (val.endsWith(EOL1) || val.endsWith(EOL2)) {
                        if (lengths.size() >= maxLines) {
                            handler.replaceRange(swingComponent, "", 0, lengths.removeFirst());
                        }
                        lengths.addLast(curLength);
                        curLength = 0;
                    }
                    handler.append(swingComponent, val);
                }

                values.clear();
                clear = false;
                queue = true;
            } finally {
                appenderLock.unlock();
            }
        }

        static private final String EOL1 = "\n";
        static private final String EOL2 = System.getProperty("line.separator", EOL1);
    }

    public interface JComponentHandler {
        void setText(JComponent swingComponent, String text);

        void replaceRange(JComponent swingComponent, String text, int start, int end);

        void append(JComponent swingComponent, String text);
    }

} /* END PUBLIC CLASS */

Exemple d'utilisation

JLabel console = new JLabel();
JComponentOutputStream consoleOutputStream = new JComponentOutputStream(console, new JComponentHandler() {
    private StringBuilder sb = new StringBuilder();

    @Override
    public void setText(JComponent swingComponent, String text) {
        sb.delete(0, sb.length());
        append(swingComponent, text);
    }

    @Override
    public void replaceRange(JComponent swingComponent, String text, int start, int end) {
        sb.replace(start, end, text);
        redrawTextOf(swingComponent);
    }

    @Override
    public void append(JComponent swingComponent, String text) {
        sb.append(text);
        redrawTextOf(swingComponent);
    }

    private void redrawTextOf(JComponent swingComponent) {
        ((JLabel)swingComponent).setText("<html><pre>" + sb.toString() + "</pre></html>");
    }
});

PrintStream con = new PrintStream(consoleOutputStream);
System.setOut(con);
System.setErr(con);    

// Optional: add a scrollpane around the console for having scrolling bars
JScrollPane sp = new JScrollPane( //
        console, //
        ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED, //
        ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED //
);
myPanel.add(sp);