如何在不删除先前绘制的内容的情况下在swing中重新绘制

import javax.swing.JPanel;
import java.awt.Graphics;

public class CustomPanel extends JPanel {
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        // 在这里实现绘制的逻辑
    }
}

import javax.swing.JFrame;

public class Main {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Swing绘图示例");
        CustomPanel panel = new CustomPanel();
        frame.add(panel);
        frame.setSize(400, 400);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

panel.repaint();