在Java Swing中创建两个标题(使用TitledBorder)时AddDocumentListener的变量作用域

import javax.swing.*;
import javax.swing.border.TitledBorder;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;

public class SwingExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Swing Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        JTextField textField = new JTextField();
        textField.getDocument().addDocumentListener(new MyDocumentListener());
        
        TitledBorder titledBorder = BorderFactory.createTitledBorder("Title 1");
        textField.setBorder(titledBorder);
        
        JTextArea textArea = new JTextArea();
        textArea.getDocument().addDocumentListener(new MyDocumentListener());
        
        titledBorder = BorderFactory.createTitledBorder("Title 2");
        textArea.setBorder(titledBorder);
        
        frame.getContentPane().add(textField);
        frame.getContentPane().add(textArea);
        
        frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
        frame.pack();
        frame.setVisible(true);
    }
    
    static class MyDocumentListener implements DocumentListener {
        @Override
        public void insertUpdate(DocumentEvent e) {
            // 文本内容插入时的处理逻辑
        }
        
        @Override
        public void removeUpdate(DocumentEvent e) {
            // 文本内容删除时的处理逻辑
        }
        
        @Override
        public void changedUpdate(DocumentEvent e) {
            // 文本内容改变时的处理逻辑
        }
    }
}