Crear una consola Java dentro de un panel de GUI

¿Cómo puedo crear una instancia de la consola Java dentro de un panel de GUI?

Aquí hay una clase funcional Puede instalar una instancia de esto en el sistema y errar usando:

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

Actualizado el 19/02/2014 : Para utilizar EventQueue.invokeLater () para evitar problemas de enrutamiento de GUI que pueden aparecer muy raramente con el original.

Actualizado el 27-02-2014 : mejor implementación

Actualizado el 29/03/2016 : Corregir la grabación y eliminación de líneas en el área de texto para que estén dentro del método run() para evitar la condición de carrera entre agregar y eliminar, lo que puede suceder si la consola se inunda con la salida. El resultado final me parece más limpio, también.

 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 lengths; // length of lines within text area private final List 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(); values =new ArrayList(); 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 */ 

Y aquí hay una captura de pantalla en acción:

enter image description here

@Sofware Monkey:

¡Funciona! 🙂

 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 ); } } } 

Sé que este es un tema viejo, pero el hecho de que lo encontré al tratar de descubrir una buena forma de hacerlo significa que probablemente otros también lo harán.

Esta es una forma (probablemente) más limpia de hacer lo que el mono de software publicó:

 import java.io.IOException; import java.io.OutputStream; import java.util.ArrayList; import javax.swing.JTextArea; /** * Represents a console viewable through a JTextArea. * * 

* Implementation: * * System.setOut(new PrintStream(new Console( ... ))); * *

* * @author Derive McNeill * */ public class Console extends OutputStream { /** * Represents the data written to the stream. */ ArrayList data = new ArrayList (); /** * 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) 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 se puede utilizar para omitir el almacenamiento en búfer.

 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); } 

En lugar de limitar el número de línea, puede vincular ByteArrayOutputStream # reset () a algún botón.

 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); } 

Recientemente utilicé el excelente código provisto por Lawrence Dol en uno de mis proyectos.

Sin embargo, en mi caso, el código consumió demasiada memoria. JTextarea reducir drásticamente la cantidad de memoria reemplazando JTextarea por un JLabel .

Mis búsquedas de almacenamiento de memoria mostraron que el código interno de JTextarea tiende a mantener el texto real enviado demasiado tiempo. En consecuencia, todo este texto no podría ser basura recolectada.

Aquí está la versión flexible del código inicial (con sincronización de hilo reemplazado por lockings).

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 lengths; // length of lines within // text area private final List 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(); values = new ArrayList(); 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 */ 

Uso de muestra

 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("
" + sb.toString() + "

"); } }); 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);