当前位置：首页 > PHP

php怎么实现依赖注入

2026-04-03 09:47:26PHP

依赖注入的实现方法

在PHP中实现依赖注入（Dependency Injection, DI）通常有以下几种方式：

构造函数注入

通过类的构造函数传递依赖对象。这是最常见的方式，适合强制依赖项。

class DatabaseService {
    private $connection;

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

$connection = new PDO('mysql:host=localhost;dbname=test', 'user', 'pass');
$databaseService = new DatabaseService($connection);

setter方法注入

通过setter方法设置依赖对象。适合可选依赖项或需要动态更换依赖的情况。

php怎么实现依赖注入

class Logger {
    private $writer;

    public function setWriter(WriterInterface $writer) {
        $this->writer = $writer;
    }
}

$logger = new Logger();
$logger->setWriter(new FileWriter());

接口注入

依赖项通过接口定义，实现类必须提供注入方法。

interface InjectLogger {
    public function inject(Logger $logger);
}

class UserService implements InjectLogger {
    private $logger;

    public function inject(Logger $logger) {
        $this->logger = $logger;
    }
}

使用容器实现DI

依赖注入容器可以自动管理对象的创建和依赖关系：

php怎么实现依赖注入

简单容器实现

class Container {
    private $services = [];

    public function register(string $name, callable $resolver) {
        $this->services[$name] = $resolver;
    }

    public function get(string $name) {
        if (!isset($this->services[$name])) {
            throw new Exception("Service not found: {$name}");
        }
        return $this->services[$name]($this);
    }
}

$container = new Container();
$container->register('db', function() {
    return new PDO('mysql:host=localhost;dbname=test', 'user', 'pass');
});
$container->register('userService', function($container) {
    return new UserService($container->get('db'));
});

使用现有DI框架

主流PHP框架都提供DI容器：

Laravel容器示例

// 绑定
app()->bind('mailer', function($app) {
    return new Mailer($app->make('config'));
});

// 解析
$mailer = app()->make('mailer');

Symfony容器示例

# services.yaml
services:
    App\Mail\Mailer:
        arguments: ['@mail.transport']

自动装配实现

现代框架支持基于类型提示的自动依赖解析：

class OrderService {
    public function __construct(
        private PaymentGateway $gateway,
        private LoggerInterface $logger
    ) {}
}

// 容器会自动解析并注入PaymentGateway和LoggerInterface的实现
$orderService = $container->get(OrderService::class);