如何从模型中获取Zend\Db\Adapter实例？(ZF2)

// Module.php
public function getServiceConfig()
{
    return array(
        'factories' => array(
            'Zend\Db\Adapter\AdapterInterface' => function($sm) {
                $adapter = new Adapter($sm);
                $adapter->setDbTableGateway($sm->get('Zend\Db\Adapter\DbTableGateway'));
                return $adapter;
            },
        ),
    );
}

// Model.php
public function __construct(Adapter $adapter)
{
    $this->adapter = $adapter;
}

// Module.php
public function getServiceConfig()
{
    return array(
        'factories' => array(
            'Zend\Db\Adapter\Platform\Sqlserver' => function($sm) {
                $adapter = new Platform\Sqlserver($sm);
                $adapter->setDbTableGateway($sm->get('Zend\Db\Adapter\DbTableGateway'));
                return $adapter;
            },
        ),
    );
}