PHP 类 方法 class function

<?php
class Site { 
    var $url;
    function setUrl($para) {
        $this->url = $para;
    }

    function getUrl() {
        echo $this->url;
    }
}

$mi = new Site;
$mi->setUrl("chanpinxue.cn");
$mi->getUrl();
?>


<?php
class SiteInfo { 
    var $url;

    function __construct($para) {
        $this->url = $para;
    }

    function setUrl($para){
        $this->url = $para;
    }

    function getUrl(){
        echo $this->url;
    }
}

$my = new SiteInfo("idodo");
$my->getUrl();
?>