常用的四种设计模式 PHP代码

　　

// 工厂模式

interface Iuser
{
    public function getUserName();
}

class UserFactory
{
    static public function load($className)
    {
        return new strtolower($className);
    }

    static public function create($className)
    {
        return new strtolower($className);
    }
}

class User implements Iuser
{
    public function getUserName()
    {
        return 'jack';
    }
}

UserFactory::create('User')->getUserName();

// 单例模式

class Singleton
{
    static public function getInstance()
    {
        static $obj = null;

        if($obj == null) {
            return new Singleton();
        }
        return $obj;
    }

    public function getUserName()
    {
        return 'jack';
    }
}

Singleton::getInstance()->getUserName();

// 观察者模式

interface Observe
{
    public function getUserName();
}

class User
{
    private $servs = [];
    public function register($obj)
    {
        array_push($servs, $obj);
        return $this;
    }

    public function triggle()
    {
        if($this->servs) {
            foreach($this->servs as $key => $value) {
                $value->getUserName();
            }
        }
    }
}

Class MyUser extends User implements Observ
{
    public function getUserName()
    {
        return 'jack';
    }
}

(new User())->register(new MyUser)->triggle();

// 策略模式

interface Human
{
    function speak();
}

class Chinese implements Human
{

    public function speak()
    {
        echo '中国人说中文';
    }
}

class American implements Human
{

    public function speak()
    {
        echo '美国人说英文';
    }
}