如何在当前位置周围画一个圆？

尝试这个。当您查看有关绘画的教程或查阅Java API时，将进行解释。我用了mouseListener一个按钮。它在您单击按钮的位置周围绘制了一个圆圈。

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Main extends JPanel {
    int width = 500;
    int height = 500;
    JFrame frame = new JFrame();
    int x;
    int y; 
    int diameter = 60;
    List<Point> points = new ArrayList<>();
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new Main());
    }

    public Main() {
        setPreferredSize(new Dimension(width, height));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBackground(Color.white);
        addMouseListener(new MyMouseListener());
        frame.add(this);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);

    }
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D) g.create();
              g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
        g2d.setColor(Color.blue);
        g2d.setStroke(new BasicStroke(3));
        for(Point p : points) {
            g2d.drawOval(p.x,p.y, diameter,diameter);
        }

    }

    private class MyMouseListener extends MouseAdapter {
        public void mouseClicked(MouseEvent me) {
            x = me.getX()-diameter/2;
            y = me.getY()-diameter/2;
            points.add(new Point(x,y));
            repaint();
        }
    }
}

回答来源：Stack Overflow