哪些PHP OOP示例是PHP OOP结构的"常见"实践？

PHP面向对象编程(OOP)常见实践

PHP面向对象编程(OOP)有一些被广泛认可的最佳实践和常见模式，以下是主要的实践示例：

1. 类与对象基础

class User {
    // 属性
    private $name;
    private $email;
    
    // 构造方法
    public function __construct($name, $email) {
        $this->name = $name;
        $this->email = $email;
    }
    
    // 方法
    public function getName() {
        return $this->name;
    }
    
    public function sendEmail($subject, $message) {
        // 发送邮件逻辑
    }
}

// 使用
$user = new User('John Doe', 'john@example.com');
echo $user->getName();

2. 继承与多态

abstract class Animal {
    protected $name;
    
    public function __construct($name) {
        $this->name = $name;
    }
    
    abstract public function makeSound();
}

class Dog extends Animal {
    public function makeSound() {
        return "Woof!";
    }
}

class Cat extends Animal {
    public function makeSound() {
        return "Meow!";
    }
}

// 多态示例
$animals = [
    new Dog('Buddy'),
    new Cat('Whiskers')
];

foreach ($animals as $animal) {
    echo $animal->makeSound();
}

3. 接口与实现

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

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

class DatabaseLogger implements Logger {
    public function log($message) {
        // 数据库记录逻辑
    }
}

// 使用
function process(Logger $logger) {
    $logger->log('Processing started');
}

$logger = new FileLogger();
process($logger);

4. 封装与访问控制

class BankAccount {
    private $balance = 0;
    
    public function deposit($amount) {
        if ($amount > 0) {
            $this->balance += $amount;
        }
    }
    
    public function withdraw($amount) {
        if ($amount > 0 && $amount <= $this->balance) {
            $this->balance -= $amount;
            return true;
        }
        return false;
    }
    
    public function getBalance() {
        return $this->balance;
    }
}

5. 静态属性和方法

class MathOperations {
    public static $pi = 3.14159;
    
    public static function add($a, $b) {
        return $a + $b;
    }
}

// 使用
echo MathOperations::$pi;
echo MathOperations::add(5, 3);

6. 魔术方法

class Magic {
    private $data = [];
    
    public function __set($name, $value) {
        $this->data[$name] = $value;
    }
    
    public function __get($name) {
        return $this->data[$name] ?? null;
    }
    
    public function __call($name, $arguments) {
        echo "Calling method '$name' with arguments: " . implode(', ', $arguments);
    }
}

$magic = new Magic();
$magic->property = 'value'; // 调用__set
echo $magic->property;      // 调用__get
$magic->undefinedMethod('arg1', 'arg2'); // 调用__call

7. 依赖注入

interface DatabaseConnection {
    public function query($sql);
}

class MySQLConnection implements DatabaseConnection {
    public function query($sql) {
        // MySQL查询逻辑
    }
}

class UserRepository {
    private $db;
    
    public function __construct(DatabaseConnection $db) {
        $this->db = $db;
    }
    
    public function getUsers() {
        return $this->db->query("SELECT * FROM users");
    }
}

// 使用
$db = new MySQLConnection();
$userRepo = new UserRepository($db);
$users = $userRepo->getUsers();

8. 单例模式

class Database {
    private static $instance = null;
    private $connection;
    
    private function __construct() {
        $this->connection = new PDO("mysql:host=localhost;dbname=test", "user", "pass");
    }
    
    public static function getInstance() {
        if (self::$instance === null) {
            self::$instance = new self();
        }
        return self::$instance;
    }
    
    public function getConnection() {
        return $this->connection;
    }
}

// 使用
$db = Database::getInstance();
$conn = $db->getConnection();

9. 工厂模式

interface PaymentMethod {
    public function pay($amount);
}

class CreditCardPayment implements PaymentMethod {
    public function pay($amount) {
        echo "Paying $amount via Credit Card";
    }
}

class PayPalPayment implements PaymentMethod {
    public function pay($amount) {
        echo "Paying $amount via PayPal";
    }
}

class PaymentFactory {
    public static function create($type) {
        switch ($type) {
            case 'credit':
                return new CreditCardPayment();
            case 'paypal':
                return new PayPalPayment();
            default:
                throw new Exception("Unknown payment method");
        }
    }
}

// 使用
$payment = PaymentFactory::create('credit');
$payment->pay(100);

10. 特征(Traits)

trait Loggable {
    public function log($message) {
        echo "Logging: $message";
    }
}

class User {
    use Loggable;
    
    public function create() {
        $this->log("User created");
    }
}

$user = new User();
$user->create();

这些示例涵盖了PHP OOP中最常见的实践模式，包括类设计、继承、接口、封装、设计模式等。遵循这些实践可以帮助编写更清晰、更可维护的面向对象PHP代码。