如何使用BorderLayout(Java)扩展JTextField

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

public class BorderLayoutExample extends JFrame {
    public BorderLayoutExample() {
        setTitle("BorderLayout Example");
        setSize(400, 200);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}

JTextField textField = new JTextField(20);

JPanel panel = new JPanel(new BorderLayout());

panel.add(textField, BorderLayout.CENTER);

add(panel);

setVisible(true);

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

public class BorderLayoutExample extends JFrame {
    public BorderLayoutExample() {
        setTitle("BorderLayout Example");
        setSize(400, 200);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JTextField textField = new JTextField(20);

        JPanel panel = new JPanel(new BorderLayout());
        panel.add(textField, BorderLayout.CENTER);

        add(panel);
        setVisible(true);
    }

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