用java实现扫雷游戏，且给出代码，并满足以下要求：首先能自动生成地雷的布局。其次玩家可以自己选择难度。然后创建一个“File”菜单，该菜单具有如下菜单项：New Game、Reset Game 和 Exit。

在 Java 中实现扫雷游戏，可以使用 Swing 库来创建图形界面。下面是一个示例代码，它满足您的要求：

import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;

public class MineSweeper extends JFrame implements ActionListener {
private static final long serialVersionUID = 1L;
private static final int EASY = 8;
private static final int MEDIUM = 16;
private static final int HARD = 24;
private static final int MINES = 10;

private JMenuItem newGameItem;
private JMenuItem resetGameItem;
private JMenuItem exitItem;

private JButton[][] buttons;
private boolean[][] mines;
private boolean[][] revealed;
private int rows;
private int cols;
private int minesLeft;

public MineSweeper() {
// 创建菜单栏
JMenuBar menuBar = new JMenuBar();
JMenu fileMenu = new JMenu("File");
newGameItem = new JMenuItem("New Game");
resetGameItem = new JMenuItem("Reset Game");
exitItem = new JMenuItem("Exit");
newGameItem.addActionListener(this);
resetGameItem.addActionListener(this);
exitItem.addActionListener(this);
fileMenu.add(newGameItem);
fileMenu.add(resetGameItem);
fileMenu.add(exitItem);
menuBar.add(fileMenu);
setJMenuBar(menuBar);

// 让玩家选择难度
Object[] options = { "Easy", "Medium", "Hard" };
int choice = JOptionPane.showOptionDialog(null, "Choose difficulty:", "Difficulty",
JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE, null, options, options[0]);
if (choice == 0) {
rows = EASY;
cols = EASY;
} else if (choice == 1) {
rows = MEDIUM;
cols = MEDIUM;
} else {
rows = HARD;
cols = HARD;
}

// 初始化游戏
minesLeft = MINES;
mines = new boolean[rows][cols];
revealed = new boolean[rows][cols];
buttons = new JButton