php __set() 重载方法意外行为

Question

我有：

class Address {
    private $number;
    private $street;

    public function __construct( $maybenumber, $maybestreet = null ) {
        if( is_null( $maybestreet) ) {
            $this->streetaddress = $maybenumber;
        } else {
            $this->number = $maybenumber;
            $this->street = $maybestreet;
        }
    }

    public function __set( $property, $value ) {
        if( $property === "streetaddress" ) {
            if( preg_match( "/^(\d+.*?)[\s,]+(.+)$/", $value, $matches ) ) {
                $this->number = $matches[1];
                $this->street = $matches[2];
            } else {
                throw new Exception( "unable to parse street address: '{$value}'" );
            }
        }
    }

    public function __get( $property ) {
        if( $property === "streetaddress" ) {
            return $this->number . " " . $this->street;
        }
    }
}

$address = new Address( "441b Bakers Street" );
echo "<pre>";
print_r($GLOBALS);
echo "</pre>";

输出：

 ...

[address] => Address Object
        (
            [number:Address:private] => 441b
            [street:Address:private] => Bakers Street
        )

如何调用__set 方法并设置属性$number 和$street 当__set 方法甚至没有从任何地方调用？

我的正常逻辑告诉我，当实例化发生时，所有会发生的事情是使用传递给$maybenumber 参数的值创建属性streetaddress，因为第二个参数$maybestreet 为空.

对此行为的任何解释都会有所帮助，并且官方文档的链接也很好。

Answer 1

您的对象没有streetaddress 属性，这就是为什么当您尝试设置它$this->streetaddress = $maybenumber; 时会调用魔术方法__set。

魔法方法：http://php.net/manual/en/language.oop5.magic.php