用java在界面中画一个15*15五子棋棋盘鼠标点击的地方画一个黑色的圈

好的，下面是Java代码实现：

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

public class GobangBoard extends JFrame {
    private int ROWS = 15;//行数
    private int COLS = 15;//列数
    private int GRID_SIZE = 30;//格子大小
    private int MARGIN = 30;//边距
    private int x, y;//鼠标点击的坐标

    public GobangBoard() {
        setTitle("五子棋");
        setSize(ROWS * GRID_SIZE + 2 * MARGIN, COLS * GRID_SIZE + 2 * MARGIN);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setResizable(false);
        addMouseListener(new MouseAdapter() {
            public void mouseClicked(MouseEvent e) {
                x = (e.getX() - MARGIN + GRID_SIZE / 2) / GRID_SIZE;
                y = (e.getY() - MARGIN + GRID_SIZE / 2) / GRID_SIZE;
                repaint();
            }
        });
        setVisible(true);
    }

    public void paint(Graphics g) {
        super.paint(g);
        for (int i = 0; i < ROWS; i++) {
            g.drawLine(MARGIN, MARGIN + i * GRID_SIZE, MARGIN + (COLS - 1) * GRID_SIZE, MARGIN + i * GRID_SIZE);
        }
        for (int i = 0; i < COLS; i++) {
            g.drawLine(MARGIN + i * GRID_SIZE, MARGIN, MARGIN + i * GRID_SIZE, MARGIN + (ROWS - 1) * GRID_SIZE);
        }
        if (x >= 0 && x < ROWS && y >= 0 && y < COLS) {
            g.setColor(Color.BLACK);
            g.fillOval(MARGIN + x * GRID_SIZE - GRID_SIZE / 2, MARGIN + y * GRID_SIZE - GRID_SIZE / 2, GRID_SIZE, GRID_SIZE);
        }
    }

    public static void main(String[] args) {
        new GobangBoard();
    }
}

运行后，界面上会显示一个15*15的五子棋棋盘。当鼠标点击棋盘上的某个位置时，会在该位置画一个黑色的圆圈。