我正在尝试为程序创建一个 GUI 面板，我希望将通常会打印到我的命令提示符的所有内容打印到 TextArea 对象。我的 GUI 面板大部分都已格式化，但我无法将文本打印到 TextArea，这是我的文件:

package guipanel;

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


/**
 *
 * @author Dan
 */
public class GUIPanel extends JFrame { 
    public GUIPanel() {
        initComponents();
    }
    private void setOutputStream(boolean catchErrors) {
        System.setOut(aPrintStream); 
        setVisible(true);
        requestFocus();
        if (catchErrors) {
               System.setErr(aPrintStream);
        }
    }
    private void addTabs(JTabbedPane jTabbedPane1) {
        JPanel jPanel1 = new JPanel();
        JPanel jPanel2 = new JPanel();
        JPanel jPanel3 = new JPanel();
        JPanel jPanel4 = new JPanel();
        jTabbedPane1.add("Main", textArea1);
        jTabbedPane1.add("Commands", jPanel);
        jTabbedPane1.add("Rules", jPanel1);
        jTabbedPane1.add("Links", jPanel2);
        jTabbedPane1.add("Information", jPanel3);
        jTabbedPane1.add("Shutdown", jPanel4);
        setOutputStream(true);
    }
    @SuppressWarnings("unchecked")
    private void initComponents() {

        textArea1 = new java.awt.TextArea();
        jTabbedPane1 = new javax.swing.JTabbedPane();
        jMenuBar1 = new javax.swing.JMenuBar();
        jMenu1 = new javax.swing.JMenu();
        jMenu2 = new javax.swing.JMenu();

        textArea1.setPreferredSize(new java.awt.Dimension(432, 343));
        textArea1.getAccessibleContext().setAccessibleParent(jTabbedPane1);

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("Evolution-X 639");
        setBounds(new java.awt.Rectangle(0, 0, 400, 450));
        setResizable(false);
        getContentPane().setLayout(new java.awt.FlowLayout());

        addTabs(jTabbedPane1);
        getContentPane().add(jTabbedPane1);

        jMenu1.setText("File");
        jMenuBar1.add(jMenu1);

        jMenu2.setText("Edit");
        jMenuBar1.add(jMenu2);

        setJMenuBar(jMenuBar1);

        pack();
    }
    public static void main(String args[]) {
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(GUIPanel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(GUIPanel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(GUIPanel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(GUIPanel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new GUIPanel().setVisible(true);
            }
        });
    }
    private JMenu jMenu1;
    private JMenu jMenu2;
    private JMenuBar jMenuBar1;
    private JTabbedPane jTabbedPane1;
    private TextArea textArea1;
    private JPanel jPanel = new JPanel();
    private PrintStream aPrintStream  =
       new PrintStream(
         new FilterOutputStream(
           new ByteArrayOutputStream()));
}

最佳答案

您需要将打印流重定向到您可以控制的输出流...

这是我为我正在工作的应用程序开发的概念示例。当它在用户站点运行时，我们使用它来调出输出控制台，这样我们就可以看到发送到标准输出的内容……直到我们修复了我们的日志记录；)

基本上，它在打印流和控制台之间放置一个自定义 OutputStream 来捕获输出，但仍然允许将内容打印到控制台。如果您从命令行或 IDE 运行程序，这将很有帮助。如果你愿意，你可以设置一个开关来停止它......

public class TestRedirect {

    public static void main(String[] args) {
        new TestRedirect();
    }

    public TestRedirect() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException ex) {
                } catch (InstantiationException ex) {
                } catch (IllegalAccessException ex) {
                } catch (UnsupportedLookAndFeelException ex) {
                }

                CapturePane capturePane = new CapturePane();
                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(capturePane);
                frame.setSize(200, 200);
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);

                PrintStream ps = System.out;
                System.setOut(new PrintStream(new StreamCapturer("STDOUT", capturePane, ps)));

                System.out.println("Hello, this is a test");
                System.out.println("Wave if you can see me");
            }            
        });
    }

    public class CapturePane extends JPanel implements Consumer {

        private JTextArea output;

        public CapturePane() {
            setLayout(new BorderLayout());
            output = new JTextArea();
            add(new JScrollPane(output));
        }

        @Override
        public void appendText(final String text) {
            if (EventQueue.isDispatchThread()) {
                output.append(text);
                output.setCaretPosition(output.getText().length());
            } else {

                EventQueue.invokeLater(new Runnable() {
                    @Override
                    public void run() {
                        appendText(text);
                    }
                });

            }
        }        
    }

    public interface Consumer {        
        public void appendText(String text);        
    }

    public class StreamCapturer extends OutputStream {

        private StringBuilder buffer;
        private String prefix;
        private Consumer consumer;
        private PrintStream old;

        public StreamCapturer(String prefix, Consumer consumer, PrintStream old) {
            this.prefix = prefix;
            buffer = new StringBuilder(128);
            buffer.append("[").append(prefix).append("] ");
            this.old = old;
            this.consumer = consumer;
        }

        @Override
        public void write(int b) throws IOException {
            char c = (char) b;
            String value = Character.toString(c);
            buffer.append(value);
            if (value.equals("\n")) {
                consumer.appendText(buffer.toString());
                buffer.delete(0, buffer.length());
                buffer.append("[").append(prefix).append("] ");
            }
            old.print(c);
        }        
    }    
}

更新了工作示例。在 Windows 7、Java 6 和 Mac OS Lion Java 7 上测试

关于java - 如何将输出流设置为 TextArea，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12945537/