当前位置：首页 > PHP

php实现委托

2026-01-29 21:00:21PHP

委托模式简介

委托模式是一种对象设计模式，允许一个对象将部分功能交给另一个对象处理。在PHP中可通过接口或魔术方法实现类似功能，常用于事件处理、中间件等场景。

通过接口实现委托

定义接口规范委托对象必须实现的方法，主类持有委托对象引用并调用其方法：

interface TaskDelegate {
    public function executeTask(string $data): string;
}

class DelegateImplementation implements TaskDelegate {
    public function executeTask(string $data): string {
        return "Processed: " . strtoupper($data);
    }
}

class MainClass {
    private $delegate;

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

    public function run(string $input) {
        return $this->delegate->executeTask($input);
    }
}

// 使用示例
$delegate = new DelegateImplementation();
$main = new MainClass($delegate);
echo $main->run("test data"); // 输出: Processed: TEST DATA

使用魔术方法实现动态委托

通过__call魔术方法实现动态方法转发，适合不确定委托对象方法的场景：

class DynamicDelegate {
    public function handleRequest($param) {
        return "Dynamic handling: " . $param;
    }
}

class Delegator {
    private $delegate;

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

    public function __call($method, $args) {
        if (method_exists($this->delegate, $method)) {
            return call_user_func_array(
                [$this->delegate, $method], 
                $args
            );
        }
        throw new BadMethodCallException("Method {$method} not found");
    }
}

// 使用示例
$delegate = new DynamicDelegate();
$proxy = new Delegator($delegate);
echo $proxy->handleRequest('value'); // 输出: Dynamic handling: value

闭包作为委托

PHP的闭包特性可以直接作为可调用委托：

class EventDispatcher {
    private $listeners = [];

    public function addListener(string $event, callable $handler) {
        $this->listeners[$event][] = $handler;
    }

    public function dispatch(string $event, $data = null) {
        foreach ($this->listeners[$event] ?? [] as $handler) {
            $handler($data);
        }
    }
}

// 使用示例
$dispatcher = new EventDispatcher();
$dispatcher->addListener('user.login', function($user) {
    echo "User logged in: {$user}\n";
});
$dispatcher->dispatch('user.login', 'admin'); // 输出: User logged in: admin

委托与DI容器结合

在现代框架中常通过依赖注入容器管理委托关系：

interface LoggerInterface {
    public function log(string $message);
}

class FileLogger implements LoggerInterface {
    public function log(string $message) {
        file_put_contents('app.log', $message.PHP_EOL, FILE_APPEND);
    }
}

class Service {
    private $logger;

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

    public function doWork() {
        $this->logger->log('Service executed');
    }
}

// 容器配置示例（伪代码）
$container->set(LoggerInterface::class, FileLogger::class);
$service = $container->get(Service::class);
$service->doWork(); // 委托FileLogger记录日志