Question

我是Java的真正初学者，正在尝试将控制台输出重定向到我用Java（Netbeans）制作的GUI的TextArea。

这是一个较大项目的一部分，但是我首先创建了一个小程序，该程序将数据输出到控制台和一个GUI，该GUI只读取这一行。有人可以帮我完成这项工作吗？我已经尝试了几种包含append，JFrame等的解决方案，但仍然没有成功。

提前谢谢！

在控制台上显示文本的程序是：

public class ConsoleToGUI {

    public void run(){
        for (int i = 0; i < 5; i++){
            System.out.println("Test program");
        }
    }

    public static void main(String[] args){
        ConsoleToGUI ctg = new ConsoleToGUI();
        ctg.run();
    }

我使用TextArea创建的GUI：
enter image description here
更新在下面，我已经发布了三个剂量（包括GUI代码），这三个剂量是由于剂量剂的解决方案而进行了调整的，谢谢！但是，我可能仍在做一些错误的事情，因为它到目前为止还无法正常工作。请您指教！

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

public class ConsoleToGUI {

public ConsoleToGUI() {
    DisplayUI gui = new DisplayUI();
    System.setOut(new PrintStream(new RedirectingOutputStream(gui), true));
    gui.start();
}


public void run(){

    for (int i = 0; i < 5; i++){
    JTextArea jTextArea1 = new JTextArea();
    System.out.println("Test program");
    }
}

public static void main(String[] args){
    ConsoleToGUI ctg = new ConsoleToGUI();
    ctg.run();
 }
}

GUI类

public class DisplayUI extends javax.swing.JFrame {

/**
 * Creates new form DislapUI
 */
public DisplayUI() {
    initComponents();
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    jPanel1 = new javax.swing.JPanel();
    jScrollPane1 = new javax.swing.JScrollPane();
    jTextArea1 = new javax.swing.JTextArea();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jPanel1.setBorder(javax.swing.BorderFactory.createTitledBorder(null, 
    "Console Output: ", 
    javax.swing.border.TitledBorder.DEFAULT_JUSTIFICATION, 
    javax.swing.border.TitledBorder.DEFAULT_POSITION, new 
    java.awt.Font("Tahoma", 1, 11), new java.awt.Color(51, 153, 255))); // 
    NOI18N

    jTextArea1.setEditable(false);
    jTextArea1.setColumns(20);
    jTextArea1.setRows(5);
    jScrollPane1.setViewportView(jTextArea1);

    javax.swing.GroupLayout jPanel1Layout = new 
    javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 348, Short.MAX_VALUE)
            .addContainerGap())
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 70, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(15, Short.MAX_VALUE))
    );

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addContainerGap())
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
    );

    pack();
}// </editor-fold>                        

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    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(DisplayUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(DisplayUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(DisplayUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(DisplayUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new DisplayUI().setVisible(true);
        }
    });
}

public void start() {
    jPanel1.setVisible(true);
}

public void appendText(String text) {
    jTextArea1.append(text);
}

// Variables declaration - do not modify                     
private javax.swing.JPanel jPanel1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea jTextArea1;
// End of variables declaration

}

RedirectingOutputStream
导入java.io.IOException; 导入java.io.OutputStream;

public class RedirectingOutputStream extends OutputStream {

    private DisplayUI gui;

    public RedirectingOutputStream(DisplayUI gui) {
        this.gui = gui;
    }

    @Override
    public void write(int b) throws IOException {
        gui.appendText(String.valueOf((char) b));
    }
 }

Answer 1

如果要在清除JTextArea后写入它，可以使用以下内容：

jTextArea.setText("Test program");

如果您希望新文本出现在较旧的文本之后：

jTextArea.append("Test program");

Answer 2

如果您的目标是将所有输出捕获到System.out（您的代码段向我建议），则可能需要执行以下操作：

创建PrintStream的子类，该子类在其write方法中也（或仅）重定向到文本区域。
将新的PrintStream设置为System.out

有关JavaFX的信息，请参见this example（除了它们没有转发到Swing组件，但从概念上讲是相同的）。

示例：

package example;

import java.io.PrintStream;

public class ConsoleToGUI {

    public ConsoleToGUI() {
        GUI gui = new GUI();
        System.setOut(new PrintStream(new RedirectingOutputStream(gui), true));
        gui.start();
    }

    public void run() {
        for (int i = 0; i < 5; i++) {
            System.out.println("Test program");
        }
    }

    public static void main(String[] args) {
        ConsoleToGUI ctg = new ConsoleToGUI();
        ctg.run();
    }
}

package example;

import java.awt.BorderLayout;

import javax.swing.JFrame;
import javax.swing.JTextArea;

public class GUI {

    private JTextArea textArea;
    private JFrame frame;

    public GUI() {
        frame = new JFrame("Example");
        frame.setBounds(0, 0, 600, 400);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        textArea = new JTextArea();
        frame.getContentPane().add(textArea, BorderLayout.CENTER);
    }

    public void start() {
        frame.setVisible(true);
    }

    public void appendText(String text) {
        textArea.append(text);
    }
}

package example;

import java.io.IOException;
import java.io.OutputStream;

public class RedirectingOutputStream extends OutputStream {

    private GUI gui;

    public RedirectingOutputStream(GUI gui) {
        this.gui = gui;
    }

    @Override
    public void write(int b) throws IOException {
        gui.appendText(String.valueOf((char) b));
    }
}

从控制台输出到GUI Java中的TextArea

2 个答案: