ZF2：TableGateway ResultSet到JSON

Question

I am trying to return data from my database to JSON in Zend Framework 2. I am using a TableGateway right now and it returns a ResultSet. But the JsonModel cannot show the resultset. So is there a way to convert it, or is there an other way to access my database?

The IndexAction in the HomeController

public function indexAction()
{
    return new JsonModel(array(
        'posts' => $posts,
        'resources' => $resources,
        'style' => $style,
        'imgStyle' => $imgStyle,
        'success' => true,
    ));
}

The function that returns the resultset

public function fetchAll()
{
    $resultSet = $this->tableGateway->select(function (Select $select) {
        $select->order('date DESC');
    });
    return $resultSet;
}