将System.out重定向到JTextPane

Question

我有一个类(如下所示)扩展JPanel并包含一个JTextPane.我想重定向System.out和System.err我JTextPane.我的班级似乎没有用.当我运行它时,它确实重定向系统打印,但它们不打印到我的JTextPane.请帮忙!

注意:仅在应用程序启动时重定向调用.但是在发布后的任何时候,System.out呼叫都不会被重定向到JTextPane.(即,如果我System.out.prinln();在类中放置一个,它将被调用,但是如果它被放置在以actionListener供以后使用,则它不会重定向).

public class OSXConsole extends JPanel {
    public static final long serialVersionUID = 21362469L;

    private JTextPane textPane;
    private PipedOutputStream pipeOut;
    private PipedInputStream pipeIn;


    public OSXConsole() {
        super(new BorderLayout());
        textPane = new JTextPane();
        this.add(textPane, BorderLayout.CENTER);

        redirectSystemStreams();

        textPane.setBackground(Color.GRAY);
        textPane.setBorder(new EmptyBorder(5, 5, 5, 5));

    }


    private void updateTextPane(final String text) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                Document doc = textPane.getDocument();
                try {
                    doc.insertString(doc.getLength(), text, null);
                } catch (BadLocationException e) {
                    throw new RuntimeException(e);
                }
                textPane.setCaretPosition(doc.getLength() - 1);
            }
        });
    }


    private void redirectSystemStreams() {
      OutputStream out = new OutputStream() {
        @Override
        public void write(final int b) throws IOException {
          updateTextPane(String.valueOf((char) b));
        }

        @Override
        public void write(byte[] b, int off, int len) throws IOException {
          updateTextPane(new String(b, off, len));
        }

        @Override
        public void write(byte[] b) throws IOException {
          write(b, 0, b.length);
        }
      };

      System.setOut(new PrintStream(out, true));
      System.setErr(new PrintStream(out, true));
    }


}

Answer 1

管道流总是让我困惑,这就是我的消息控制台解决方案不使用它们的原因.无论如何,这是我尝试使用管道流的控制台.有几点不同:

a)它使用JTextArea,因为JTextArea比JTextPane更有效,只显示文本.当然,如果您打算向文本添加属性,则需要一个文本窗格.

b)此解决方案使用线程.我确定我在某处读到这是防止阻塞输出所必需的.无论如何,它适用于我的简单测试用例.

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

public class Console implements Runnable
{
    JTextArea displayPane;
    BufferedReader reader;

    private Console(JTextArea displayPane, PipedOutputStream pos)
    {
        this.displayPane = displayPane;

        try
        {
            PipedInputStream pis = new PipedInputStream( pos );
            reader = new BufferedReader( new InputStreamReader(pis) );
        }
        catch(IOException e) {}
    }

    public void run()
    {
        String line = null;

        try
        {
            while ((line = reader.readLine()) != null)
            {
//              displayPane.replaceSelection( line + "\n" );
                displayPane.append( line + "\n" );
                displayPane.setCaretPosition( displayPane.getDocument().getLength() );
            }

            System.err.println("im here");
        }
        catch (IOException ioe)
        {
            JOptionPane.showMessageDialog(null,
                "Error redirecting output : "+ioe.getMessage());
        }
    }

    public static void redirectOutput(JTextArea displayPane)
    {
        Console.redirectOut(displayPane);
        Console.redirectErr(displayPane);
    }

    public static void redirectOut(JTextArea displayPane)
    {
        PipedOutputStream pos = new PipedOutputStream();
        System.setOut( new PrintStream(pos, true) );

        Console console = new Console(displayPane, pos);
        new Thread(console).start();
    }

    public static void redirectErr(JTextArea displayPane)
    {
        PipedOutputStream pos = new PipedOutputStream();
        System.setErr( new PrintStream(pos, true) );

        Console console = new Console(displayPane, pos);
        new Thread(console).start();
    }

    public static void main(String[] args)
    {
        JTextArea textArea = new JTextArea();
        JScrollPane scrollPane = new JScrollPane( textArea );

        JFrame frame = new JFrame("Redirect Output");
        frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        frame.getContentPane().add( scrollPane );
        frame.setSize(200, 100);
        frame.setVisible(true);

        Console.redirectOutput( textArea );
        final int i = 0;

        Timer timer = new Timer(1000, new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                System.out.println( new java.util.Date().toString() );
                System.err.println( System.currentTimeMillis() );
            }
        });
        timer.start();
    }
}

Answer 2

Message Console类为您执行此操作.

编辑:

这是一个简单的测试类:

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

public class MessageConsoleTest
{
    public static int counter;

    public static void main(String[] args)
        throws Exception
    {
        JTextComponent textComponent = new JTextPane();
        JScrollPane scrollPane = new JScrollPane( textComponent );

        JFrame.setDefaultLookAndFeelDecorated(true);
        JFrame frame = new JFrame("Message Console");
        frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        frame.getContentPane().add( scrollPane );
        frame.setSize(400, 120);
        frame.setVisible(true);

        MessageConsole console = new MessageConsole(textComponent);
        console.redirectOut();
        console.redirectErr(Color.RED, null);

        Timer timer = new Timer(1000, new java.awt.event.ActionListener()
        {
            public void actionPerformed(java.awt.event.ActionEvent e)
            {
                System.out.println( new java.util.Date().toString() );
            }
        });
        timer.start();

        Thread.sleep(750);

        Timer timer2 = new Timer(1000, new java.awt.event.ActionListener()
        {
            public void actionPerformed(java.awt.event.ActionEvent e)
            {
                System.err.println( "Error Message: " + ++counter);
            }
        });
        timer2.start();
    }
}