写一个Java程序，可以实现五子棋双人对战

以下是一个简单的 Java 五子棋双人对战程序示例，您可以参考它进行开发：

import java.util.Scanner;

public class Gobang {
    private static final int BOARD_SIZE = 15; // 棋盘大小
    private static String[][] board = new String[BOARD_SIZE][BOARD_SIZE]; // 棋盘数组

    public static void main(String[] args) {
        initBoard(); // 初始化棋盘
        printBoard(); // 打印棋盘
        Scanner scanner = new Scanner(System.in);
        int row, col;
        String player = "X";
        while (true) {
            System.out.print("请 " + player + " 下棋，输入坐标（格式如 3,5）：");
            String input = scanner.next();
            if (input.equalsIgnoreCase("exit")) {
                System.out.println("游戏结束！");
                break;
            }
            String[] coords = input.split(",");
            if (coords.length != 2) {
                System.out.println("无效的坐标，请重试！");
                continue;
            }
            try {
                row = Integer.parseInt(coords[0]) - 1;
                col = Integer.parseInt(coords[1]) - 1;
            } catch (NumberFormatException e) {
                System.out.println("无效的坐标，请重试！");
                continue;
            }
            if (row < 0 || row >= BOARD_SIZE || col < 0 || col >= BOARD_SIZE) {
                System.out.println("坐标超出棋盘范围，请重试！");
                continue;
            }
            if (board[row][col] != null) {
                System.out.println("该位置已有棋子，请重试！");
                continue;
            }
            board[row][col] = player; // 在棋盘上下子
            printBoard(); // 打印棋盘
            if (checkWin(row, col, player)) { // 判断是否胜利
                System.out.println("恭喜 " + player + " 获得胜利！");
                break;
            }
            player = player.equals("X") ? "O" : "X"; // 切换玩家
        }
        scanner.close();
    }

    private static void initBoard() {
        for (int i = 0; i < BOARD_SIZE; i++) {
            for (int j = 0; j < BOARD_SIZE; j++) {
                board[i][j] = null; // 初始化每个位置为空
            }
        }
    }

    private static void printBoard() {
        System.out.print("  ");
        for (int i = 1; i <= BOARD_SIZE; i++) {
            System.out.print(i + " ");
        }
        System.out.println();
        for (int i = 0; i < BOARD_SIZE; i++) {
            System.out.print((i + 1) + " ");
            for (int j = 0; j < BOARD_SIZE; j++) {
                if (board[i][j] == null) {
                    System.out.print("+ ");
                } else {
                    System.out.print(board[i][j] + " ");
                }
            }
            System.out.println();
        }
    }

    private static boolean checkWin(int row, int col, String player) {
        // 检查水平方向
        int count = 0;
        for (int i = col - 4; i <= col + 4; i++) {
            if (i < 0 || i >= BOARD_SIZE) {
                continue;
            }
            if (board[row][i] == player) {
                count++;
            } else {
                count = 0;
            }
            if (count >= 5) {
                return true;
            }
        }
        // 检查垂直方向
        count = 0;
        for (int i = row - 4; i <= row + 4; i++) {
            if (i < 0 || i >= BOARD_SIZE) {
                continue;
            }
            if (board[i][col] == player) {
                count++;
            } else {
                count = 0;
            }
            if (count >= 5) {
                return true;
            }
        }
        // 检查左上-右下方向
        count = 0;
        for (int i = row - 4, j = col - 4; i <= row + 4 && j <= col + 4; i++, j++) {
            if (i < 0 || i >= BOARD_SIZE || j < 0 || j >= BOARD_SIZE) {
                continue;
            }
            if (board[i][j] == player) {
                count++;
            } else {
                count = 0;
            }
            if (count >= 5) {
                return true;
            }
        }
        // 检查左下-右上方向
        count = 0;
        for (int i = row + 4, j = col - 4; i >= row - 4 && j <= col + 4; i--, j++) {
            if (i < 0 || i >= BOARD_SIZE || j < 0 || j >= BOARD_SIZE) {
                continue;
            }
            if (board[i][j] == player) {
                count++;
            } else {
                count = 0;
            }
            if (count >= 5) {
                return true;
            }
        }
        return false;
    }
}

此程序实现了一个简单的五子棋双人对战，玩家可以通过输入坐标来下棋，程序会判断胜负并打印棋盘。但这只是一个简单的示例，还有很多方面需要优化和改进，比如增加界面、加入AI等。