PHP에서 객체지향 디자인 패턴을 사용하는 방법은 무엇입니까?

interface Shape { public function draw(); } class Circle implements Shape { public function draw() { echo "Drawing a circle"; } } class Square implements Shape { public function draw() { echo "Drawing a square"; } } class ShapeFactory { public static function create($type) { switch ($type) { case 'circle': return new Circle(); case 'square': return new Square(); default: throw new Exception("Invalid shape type"); } } } $circle = ShapeFactory::create('circle'); $circle->draw(); // Output: Drawing a circle $square = ShapeFactory::create('square'); $square->draw(); // Output: Drawing a square

class Database { private static $instance; private function __construct() { // 应该在这里初始化数据库连接 } public static function getInstance() { if (!self::$instance) { self::$instance = new self(); } return self::$instance; } } $db = Database::getInstance();

class User implements SplSubject { private $observers = []; public function attach(SplObserver $observer) { $this->observers[] = $observer; } public function detach(SplObserver $observer) { $key = array_search($observer, $this->observers, true); if ($key !== false) { unset($this->observers[$key]); } } public function notify() { foreach ($this->observers as $observer) { $observer->update($this); } } } class Logger implements SplObserver { public function update(SplSubject $subject) { echo "Logging user update: " . $subject->getName(); } } $user = new User(); $user->attach(new Logger()); $user->setName("John Doe"); // Output: Logging user update: John Doe