yii2打开session                         （推荐学习：yii教程）
use yii\web\session; $session = yii::$app->session;// check if a session is already openif ($session->isactive) ...// open a session$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;$session->remove('user_id');//orunset($session['user_id']);//orunset($_session['user_id']);
以上就是yii2 如何开启session的详细内容。