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php实现接口

2026-02-13 13:18:54PHP

PHP 实现接口的方法

定义接口

接口使用 interface 关键字定义，可以包含方法声明但不包含实现。所有方法默认为公共方法。

interface PaymentGateway {
    public function processPayment($amount);
    public function refundPayment($transactionId);
}

实现接口

类使用 implements 关键字实现接口，必须提供接口中所有方法的具体实现。

class StripePayment implements PaymentGateway {
    public function processPayment($amount) {
        // Stripe 支付处理逻辑
        return "Processed payment of $amount via Stripe";
    }

    public function refundPayment($transactionId) {
        // Stripe 退款处理逻辑
        return "Refunded transaction $transactionId via Stripe";
    }
}

多接口实现

一个类可以实现多个接口，用逗号分隔。

interface Logger {
    public function log($message);
}

class PayPalPayment implements PaymentGateway, Logger {
    public function processPayment($amount) {
        // PayPal 支付处理逻辑
        return "Processed payment of $amount via PayPal";
    }

    public function refundPayment($transactionId) {
        // PayPal 退款处理逻辑
        return "Refunded transaction $transactionId via PayPal";
    }

    public function log($message) {
        // 日志记录逻辑
        echo "Log: $message";
    }
}

接口继承

接口可以继承其他接口，扩展功能。

interface AdvancedPaymentGateway extends PaymentGateway {
    public function authorize($credentials);
}

class SquarePayment implements AdvancedPaymentGateway {
    public function processPayment($amount) {
        // Square 支付处理逻辑
    }

    public function refundPayment($transactionId) {
        // Square 退款处理逻辑
    }

    public function authorize($credentials) {
        // Square 授权逻辑
    }
}

类型提示

接口可用于类型提示，确保参数实现特定接口。

function handlePayment(PaymentGateway $gateway, $amount) {
    echo $gateway->processPayment($amount);
}

$stripe = new StripePayment();
handlePayment($stripe, 100.00);

常量定义

接口可以包含常量，实现类不能覆盖这些常量。

php实现接口

interface Shipping {
    const DEFAULT_COUNTRY = 'US';

    public function calculateShipping($address);
}

class FedExShipping implements Shipping {
    public function calculateShipping($address) {
        // 使用接口常量
        if ($address['country'] === Shipping::DEFAULT_COUNTRY) {
            return 5.00;
        }
        return 15.00;
    }
}

实际应用示例

REST API 接口实现

interface ApiEndpoint {
    public function handleRequest($requestData);
}

class UserEndpoint implements ApiEndpoint {
    public function handleRequest($requestData) {
        switch ($_SERVER['REQUEST_METHOD']) {
            case 'GET':
                return $this->getUser($requestData['id']);
            case 'POST':
                return $this->createUser($requestData);
            default:
                throw new Exception('Method not allowed');
        }
    }

    private function getUser($id) {
        // 获取用户逻辑
    }

    private function createUser($data) {
        // 创建用户逻辑
    }
}

// 使用示例
$endpoint = new UserEndpoint();
try {
    $response = $endpoint->handleRequest($_REQUEST);
    echo json_encode($response);
} catch (Exception $e) {
    http_response_code(400);
    echo json_encode(['error' => $e->getMessage()]);
}

数据库访问接口

interface DatabaseAdapter {
    public function connect($config);
    public function query($sql);
    public function close();
}

class MySQLAdapter implements DatabaseAdapter {
    private $connection;

    public function connect($config) {
        $this->connection = new mysqli(
            $config['host'],
            $config['user'],
            $config['password'],
            $config['database']
        );
    }

    public function query($sql) {
        return $this->connection->query($sql);
    }

    public function close() {
        $this->connection->close();
    }
}