集合综合练习（分层开发）

实体类been包：

public class User {
    private String id;
    private String username;
    private String password;

    public User() {
    }


    public User(String id, String username, String password) {
        this.id = id;
        this.username = username;
        this.password = password;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

持久层接口以及其实现类：

public interface UserDao {
   //注册的方法
    void registerUser(User user);
    //登录的方法
    boolean login(String userName, String password);
    //判断用户名是否存在
    boolean doesItExist(String userName);
}

//实现类 用集合来模拟登录和注册
public class UserDaoImpl implements UserDao {
   private ArrayList list = new ArrayList<>();
    //注册
    @Override
    public void registerUser(User user) {

        list.add(user);
    }
    //登录
    @Override
    public boolean login(String userName, String password) {
        for (User user : list) {
            if(user.getUsername().equals(userName)&&user.getPassword().equals(password)){
                return true;
            }
        }
        return false;
    }

    @Override
    public boolean doesItExist(String userName) {
        for (User user : list) {
            if (user.getUsername().equals(userName)) {
                return  false;
            }
        }

        return true; //true代表用户名，不存在，可以注册，false代表用户名存在了不能注册
    }
}

在视图层插入的游戏类：

public class GuessNumber {
    public static void playGame() {
        Random random = new Random();
        int num = random.nextInt(100) + 1;
        Scanner sc = new Scanner(System.in);
        while (true) {
            System.out.println("请输入一个数字 1----100");
            int guessNumber = sc.nextInt();
            if (guessNumber > num) {
                System.out.println("猜大了");
            } else if (guessNumber < num) {
                System.out.println("猜小了");
            } else{
                System.out.println("恭喜你猜对了");
                break;
            }
        }
    }
}

业务层接口及其实现类：

public interface UserService {
    //注册的方法
    boolean registerUser(User user);

    //登录的方法
    boolean login(String userName, String password);

}

//业务层
public class UserServiceImpl implements UserService {
   private UserDao userDao = new UserDaoImpl();
    @Override
    public boolean registerUser(User user) {
        //业务：判断用户名是否存在，如果存在，就不能注册
        if(userDao.doesItExist(user.getUsername())){
            userDao.registerUser(user);
            return true;
        }
        return false;
    }

    @Override
    public boolean login(String userName, String password) {
        boolean b = userDao.login(userName, password);
        return b;
    }
}

工具类生成随机数字：

public class UUIDUtils {
    private UUIDUtils() {
    }
    public static String getUUID() {
        UUID uuid = UUID.randomUUID();
        return uuid.toString().replace("-","");
    }
}

视图层：

//视图层
public class UserView {

    

    public static void main(String[] args) {
        UserService userService = new UserServiceImpl();
        while (true) {
            System.out.println("---欢迎使用本系统 1 注册 2 登录 3 退出--");
            Scanner sc = new Scanner(System.in);
            if (sc.hasNextInt()) {
                int num = sc.nextInt();
                switch (num) {
                    case 1: //注册
                        while (true) {
                            sc = new Scanner(System.in);
                            System.out.println("请输入用户名");
                            String username = sc.nextLine();
                            String regx = "[A-Za-z]{6,16}";
                            System.out.println("请输入密码");
                            String password = sc.nextLine();
                            String regx1 = "[0-9]{6,16}";
                            if (username.matches(regx) && password.matches(regx1)) {
                                User user = new User(UUIDUtils.getUUID(), username, password);
                                //调用业务层注册
                                boolean b = userService.registerUser(user);
                                if (b) {
                                    System.out.println("注册成功！");
                                    break;
                                } else {
                                    System.out.println("用户名重复,请重新注册");
                                }
                            }else {
                                System.out.println("请输入正确的名字和密码格式");
                            }
                        }
                        break;
                    case 2: //登录逻辑
                        for (int i = 1; i < 4; i++) {
                            sc = new Scanner(System.in);
                            System.out.println("请输入用户名");
                            String username2 = sc.nextLine();
                            System.out.println("请输入密码");
                            String password2 = sc.nextLine();
                            //调用业务层登录
                            boolean flag = userService.login(username2, password2);
                            if (flag) {
                                System.out.println("登录成功!要玩游戏吗？y/n");
                                while (true) {
                                    String str = sc.nextLine();
                                    if ("y".equalsIgnoreCase(str)) {
                                        //玩游戏
                                        GuessNumber.playGame();
                                        System.out.println("还要要玩游戏吗？y/n");
                                    } else {
                                        System.out.println("谢谢使用再见！");
                                        System.exit(0);
                                    }
                                }

                            } else {
                                System.out.println("登录失败!你还有" + (3 - i) + "次机会");
                            }
                        }
                        break;
                    case 3: //退出
                        System.out.println("谢谢使用再见！");
                        System.exit(0);
                        break;
                }

            } else {
                System.out.println("请输入单个数字");
            }
        }
    }
}