无需点击按钮即可动态显示基于JtextArea的Jlabel

import javax.swing.*;
import java.awt.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

public class DynamicLabelExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Dynamic Label Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 200);
        
        JPanel panel = new JPanel(new BorderLayout());
        JTextArea textArea = new JTextArea();
        JLabel label = new JLabel();

        textArea.addKeyListener(new KeyListener() {
            @Override
            public void keyTyped(KeyEvent e) {
            }

            @Override
            public void keyPressed(KeyEvent e) {
            }

            @Override
            public void keyReleased(KeyEvent e) {
                String text = textArea.getText(); // 获取文本区域的内容
                label.setText(text); // 将文本设置为标签的内容
            }
        });

        panel.add(textArea, BorderLayout.NORTH);
        panel.add(label, BorderLayout.CENTER);
        frame.getContentPane().add(panel);
        frame.setVisible(true);
    }
}