如何使用zend路由器主机名路由多个子域

resources.router.routes.hostname.type = "Zend_Controller_Router_Route_Hostname"
resources.router.routes.hostname.route = ":subdomain.example.com"
resources.router.routes.hostname.defaults.module = "default"
resources.router.routes.hostname.defaults.controller = "index"
resources.router.routes.hostname.defaults.action = "index"
resources.router.routes.hostname.chains.index.type = "Zend_Controller_Router_Route_Static"
resources.router.routes.hostname.chains.index.route = ""

class IndexController extends Zend_Controller_Action
{
    public function init()
    {
        $this->_helper->layout->disableLayout();
        $this->_helper->viewRenderer->setNoRender(true);
    }

    public function indexAction()
    {
        $host = $_SERVER['HTTP_HOST'];
        $subdomain = explode('.', $host)[0];

        // 根据子域名执行相应的操作
        switch ($subdomain) {
            case 'sub1':
                // 处理sub1子域名的请求
                break;
            case 'sub2':
                // 处理sub2子域名的请求
                break;
            default:
                // 处理默认子域名的请求
                break;
        }
    }
}