java swing语言 登录注册界面 MVC架构，json格式储存，代码

以下是一个简单的 Java Swing 登录注册界面的 MVC 架构代码，并且使用 JSON 格式进行数据储存。

首先，我们需要创建一个 User 类来表示用户信息：

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

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

    public String getUsername() {
        return username;
    }

    public String getPassword() {
        return password;
    }
}

接下来，我们需要创建一个 UserDao 接口，来规定用户信息的 CRUD 操作：

public interface UserDao {
    boolean createUser(User user);
    User readUser(String username);
    boolean updateUser(User user);
    boolean deleteUser(String username);
}

然后，我们需要创建一个 UserDaoImpl 类，来实现 UserDao 接口，并且使用 JSON 格式进行数据储存：

public class UserDaoImpl implements UserDao {
    private final String fileName = "users.json";
    private final Gson gson = new Gson();

    @Override
    public boolean createUser(User user) {
        List<User> users = readUsers();
        for (User u : users) {
            if (u.getUsername().equals(user.getUsername())) {
                return false;
            }
        }
        users.add(user);
        writeUsers(users);
        return true;
    }

    @Override
    public User readUser(String username) {
        List<User> users = readUsers();
        for (User user : users) {
            if (user.getUsername().equals(username)) {
                return user;
            }
        }
        return null;
    }

    @Override
    public boolean updateUser(User user) {
        List<User> users = readUsers();
        for (int i = 0; i < users.size(); i++) {
            if (users.get(i).getUsername().equals(user.getUsername())) {
                users.set(i, user);
                writeUsers(users);
                return true;
            }
        }
        return false;
    }

    @Override
    public boolean deleteUser(String username) {
        List<User> users = readUsers();
        for (int i = 0; i < users.size(); i++) {
            if (users.get(i).getUsername().equals(username)) {
                users.remove(i);
                writeUsers(users);
                return true;
            }
        }
        return false;
    }

    private List<User> readUsers() {
        try (Reader reader = new FileReader(fileName)) {
            Type type = new TypeToken<List<User>>(){}.getType();
            return gson.fromJson(reader, type);
        } catch (IOException e) {
            return new ArrayList<>();
        }
    }

    private void writeUsers(List<User> users) {
        try (Writer writer = new FileWriter(fileName)) {
            gson.toJson(users, writer);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

接下来，我们需要创建一个 LoginView 类，来表示登录界面：

public class LoginView extends JFrame {
    private final JLabel lblUsername = new JLabel("Username:");
    private final JTextField txtUsername = new JTextField(20);
    private final JLabel lblPassword = new JLabel("Password:");
    private final JPasswordField txtPassword = new JPasswordField(20);
    private final JButton btnLogin = new JButton("Login");
    private final JButton btnRegister = new JButton("Register");

    private final LoginController loginController;

    public LoginView(LoginController loginController) {
        super("Login");
        this.loginController = loginController;

        JPanel panel = new JPanel(new GridLayout(3, 2));
        panel.add(lblUsername);
        panel.add(txtUsername);
        panel.add(lblPassword);
        panel.add(txtPassword);
        panel.add(btnLogin);
        panel.add(btnRegister);

        btnLogin.addActionListener(e -> {
            String username = txtUsername.getText();
            String password = new String(txtPassword.getPassword());
            loginController.login(username, password);
        });

        btnRegister.addActionListener(e -> {
            String username = txtUsername.getText();
            String password = new String(txtPassword.getPassword());
            loginController.register(username, password);
        });

        add(panel);
        pack();
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }
}

然后，我们需要创建一个 RegisterView 类，来表示注册界面：

public class RegisterView extends JFrame {
    private final JLabel lblUsername = new JLabel("Username:");
    private final JTextField txtUsername = new JTextField(20);
    private final JLabel lblPassword = new JLabel("Password:");
    private final JPasswordField txtPassword = new JPasswordField(20);
    private final JButton btnRegister = new JButton("Register");

    private final RegisterController registerController;

    public RegisterView(RegisterController registerController) {
        super("Register");
        this.registerController = registerController;

        JPanel panel = new JPanel(new GridLayout(2, 2));
        panel.add(lblUsername);
        panel.add(txtUsername);
        panel.add(lblPassword);
        panel.add(txtPassword);
        panel.add(btnRegister);

        btnRegister.addActionListener(e -> {
            String username = txtUsername.getText();
            String password = new String(txtPassword.getPassword());
            registerController.register(username, password);
        });

        add(panel);
        pack();
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        setVisible(true);
    }
}

接下来，我们需要创建一个 LoginController 类，来控制登录流程：

public class LoginController {
    private final UserDao userDao = new UserDaoImpl();
    private final LoginView loginView;

    public LoginController(LoginView loginView) {
        this.loginView = loginView;
    }

    public void login(String username, String password) {
        User user = userDao.readUser(username);
        if (user != null && user.getPassword().equals(password)) {
            JOptionPane.showMessageDialog(loginView, "Login successful!");
        } else {
            JOptionPane.showMessageDialog(loginView, "Invalid username or password!");
        }
    }

    public void register(String username, String password) {
        boolean result = userDao.createUser(new User(username, password));
        if (result) {
            JOptionPane.showMessageDialog(loginView, "Register successful!");
        } else {
            JOptionPane.showMessageDialog(loginView, "Username already exists!");
        }
    }
}

最后，我们需要创建一个 RegisterController 类，来控制注册流程：

public class RegisterController {
    private final UserDao userDao = new UserDaoImpl();
    private final RegisterView registerView;

    public RegisterController(RegisterView registerView) {
        this.registerView = registerView;
    }

    public void register(String username, String password) {
        boolean result = userDao.createUser(new User(username, password));
        if (result) {
            JOptionPane.showMessageDialog(registerView, "Register successful!");
            registerView.dispose();
        } else {
            JOptionPane.showMessageDialog(registerView, "Username already exists!");
        }
    }
}

现在，我们可以在主函数中创建登录界面和注册界面，并且将它们与对应的控制器进行绑定：

public class Main {
    public static void main(String[] args) {
        LoginView loginView = new LoginView(new LoginController(loginView));
        RegisterView registerView = new RegisterView(new RegisterController(registerView));
    }
}

这样，我们就完成了一个简单的 Java Swing 登录注册界面的 MVC 架构，并且使用 JSON 格式进行数据储存。