~~~ use yii\web\Session; $session = Yii::$app->session; // check if a session is already open if ($session->isActive) ... // open a session $session->open(); // close a session $session->close(); // destroys all data registered to a session. $session->destroy(); ~~~ * * * * * #### 设置session： ~~~ $session = Yii::$app->session; $session->set('user_id', '1234'); //OR $session['user_id'] = '1234'; //OR $_SESSION['user_id'] = '1234'; ~~~ * * * * * #### 读取session： ~~~ $session = Yii::$app->session; $user_id = $session->get('user_id'); //OR $user_id = $session['user_id']; //OR $user_id = isset($_SESSION['user_id']) ? $_SESSION['user_id'] : null; ~~~ * * * * * #### 销毁session： ~~~ $session = Yii::$app->session; $session->remove('user_id'); //OR unset($session['user_id']); //OR unset($_SESSION['user_id']); ~~~ * * * * * #### 数组session的读取与设置： ~~~ $session = Yii::$app->session; $session->remove('user_id'); //OR unset($session['user_id']); //OR unset($_SESSION['user_id']); ~~~