Créer une console Java dans un panneau GUI
Comment puis-je créer une instance de la console Java à l'intérieur d'un panneau GUI?
Voici une classe qui fonctionne. Vous pouvez installer une instance de ceci dans le système et errer en utilisant:
PrintStream con=new PrintStream(new TextAreaOutputStream(...));
System.setOut(con);
System.setErr(con);
Mise à jour le 2014-02-19: Pour utiliser EventQueue.invokeLater () pour éviter les problèmes de threading de l'interface graphique qui peuvent survenir très rarement avec l'original.
Mis à jour le 2014-02-27: Meilleure mise en œuvre
Mise à jour le 2014-03-25: Enregistrement et suppression corrects des lignes dans la zone de texte pour être dans la méthode run() pour éviter la condition de concurrence entre l'ajout et la suppression qui peut se produire si la console est inondé 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 en action:
@Sofware Monkey:
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 le singe logiciel a publié:
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 la mise en mémoire 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);
}
Plutôt que 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);
}
J'ai récemment utilisé le excellent code fourni par Lawrence Dol dans l'un de mes projets.
Cependant, dans mon cas, le code a consommé trop de mémoire. J'ai réussi à réduire considérablement la consommation de mémoire en remplaçant JTextarea par un JLabel.
Mes recherches d'économie de mémoire ont montré que le code interne de JTextarea a tendance à contenir trop de temps le texte réel envoyé. Par conséquent, tout ce texte n'a pas pu être récupéré.
Voici la version flexible du code initial (avec synchronisation des threads remplacée par des verrous).
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);