yii2怎么抛出自定义异常 [ 2.0 版本 ]

如题 如何抛出自定义的异常 这样可以吗

$connection = Yii::$app->db;
$transaction = $connection->beginTransaction();
try {
    $sql1 = 'insert into t_test1(name) values(2)';
    $sql2 = 'insert into t_test2(name) values(2)';
    $res1= $connection->createCommand($sql1)->execute();
    $res2= $connection->createCommand($sql2)->execute();
    if(!$res1){
        throw new \Exception('第一次错误');
    }if(!$res2){
        throw new \Exception('第二次错误');
    }
    // ... executing other SQL statements ...
    $transaction->commit();
} catch (\yii\db\Exception $e) {
    echo $e->getMessage();
    $transaction->rollBack();
}