如何在Graphics2D Java中设置文本边界？

import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class TextBoundaries extends JPanel {

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g;

        // 设置字体
        g2d.setFont(new Font("Arial", Font.PLAIN, 12));

        // 获取字体边界信息
        FontMetrics fontMetrics = g2d.getFontMetrics();
        int ascent = fontMetrics.getAscent();
        int descent = fontMetrics.getDescent();
        int stringWidth = fontMetrics.stringWidth("Hello World!");

        // 绘制文本并设置位置
        int x = getWidth() / 2 - stringWidth / 2;
        int y = getHeight() / 2 + (ascent - descent) / 2;
        g2d.drawString("Hello World!", x, y);
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Text Boundaries Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 300);
        frame.add(new TextBoundaries());
        frame.setVisible(true);
    }
}