PHP MVC 从零学起（1）

<?php
// 定义路径
define(&#39;MVC_PATH&#39;, dirname(__FILE__));
define(&#39;CONTROLLERS_PATH&#39;, MVC_PATH.&#39;/controllers&#39;);
define(&#39;VIEWS_PATH&#39;, MVC_PATH . &#39;/views&#39;);


$mod = $_REQUEST[&#39;mod&#39;] = !empty($_REQUEST[&#39;mod&#39;]) ? $_REQUEST[&#39;mod&#39;] : &#39;main&#39;;
$act = $_REQUEST[&#39;act&#39;] = !empty($_REQUEST[&#39;act&#39;]) ? $_REQUEST[&#39;act&#39;] : &#39;index&#39;;
require CONTROLLERS_PATH . &#39;/controller.php&#39;;
require CONTROLLERS_PATH . &#39;/&#39; . $mod . &#39;.php&#39;;
$c = new $mod();
$c->$act();
?>

<?php
class controller {
    
    public function display($template, $data){
        extract($data);
        ob_start();
        include VIEWS_PATH . &#39;/&#39; . $template;
        $content = ob_get_contents();
        ob_end_clean();
        exit($content);
    }
}
?>

<?php
class main extends controller {
    
    public function index(){
        $data = array(&#39;a&#39; => &#39;hello word!&#39;);
        $this->display(&#39;index.php&#39;, $data);
    }
}
?>

<?php echo $a;?>