PHP接口设计与实现的最佳实践

<?php
// 定义UserService接口
interface UserService {
    public function createUser($userData);
    public function getUserById($userId);
    public function updateUser($userId, $newUserData);
    public function deleteUser($userId);
}

// 实现UserService接口
class MySQLUserService implements UserService {
    private $db;

    public function __construct($db) {
        $this->db = $db;
    }

    public function createUser($userData) {
        // 实现创建用户的逻辑
    }

    public function getUserById($userId) {
        // 实现根据用户ID获取用户信息的逻辑
    }

    public function updateUser($userId, $newUserData) {
        // 实现更新用户信息的逻辑
    }

    public function deleteUser($userId) {
        // 实现删除用户的逻辑
    }
}

// 使用示例
$db = new PDO('mysql:host=localhost;dbname=test', 'username', 'password');
$userService = new MySQLUserService($db);

$userData = ['username' => 'Alice', 'email' => 'alice@example.com'];
$userService->createUser($userData);

$user = $userService->getUserById(1);
var_dump($user);