我有一個(gè)帶有一些普通方法的類 User 和一個(gè)傳遞 $pdo 對(duì)象的構(gòu)造函數(shù)。還有一個(gè)名為isLogged()的方法，它只檢查是否設(shè)置了必要的會(huì)話變量。但是，如果我只想檢查用戶是否已登錄，而不建立數(shù)據(jù)庫連接怎么辦？// I need to check if user is logged here but it requires including db.phprequire 'includes/db.php';$user = new User($pdo);if (!$user->isLogged()) {    header('Location: index.php');    exit;}if ($_SERVER['REQUEST_METHOD'] === 'POST') {    // POST validation    // ...    // That is the place where DB connection should be made}