在JTextField的一个帧/类/窗口中输入数字，然后在另一个JLabel中显示它

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class NumberInputFrame extends JFrame {
    private JTextField textField;
    private JLabel label;

    public NumberInputFrame() {
        setTitle("Number Input");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(300, 200);
        setLocationRelativeTo(null);

        textField = new JTextField();
        label = new JLabel();

        textField.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String input = textField.getText();
                try {
                    int number = Integer.parseInt(input);
                    label.setText("You entered: " + number);
                } catch (NumberFormatException ex) {
                    label.setText("Invalid input");
                }
            }
        });

        getContentPane().add(textField, "North");
        getContentPane().add(label, "Center");
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                NumberInputFrame frame = new NumberInputFrame();
                frame.setVisible(true);
            }
        });
    }
}