PHP重载

<strong>class Car {    private $ary = array();        public function __set($key, $val) {        $this->ary[$key] = $val;    }        public function __get($key) {        if (isset($this->ary[$key])) {            return $this->ary[$key];        }        return null;    }        public function __isset($key) {        if (isset($this->ary[$key])) {            return true;        }        return false;    }        public function __unset($key) {        unset($this->ary[$key]);    }}$car = new Car();$car->name = '汽车';  //name属性动态创建并赋值echo $car->name;</strong>

<strong>class Car {    public $speed = 0;        public function __call($name, $args) {        if ($name == 'speedUp') {            $this->speed += 10;        }    }}$car = new Car();$car->speedUp(); //调用不存在的方法会使用重载echo $car->speed;</strong>