huahuibao/app/backend/controllers/ErrorController.php

<?php

namespace backend\controllers;
use Yii;
use yii\web\Controller;

class ErrorController extends BackendController
{
    public function actionErrorPage(){
        $statusCode = Yii::$app->request->get('statusCode');

        switch ($statusCode){
            case 'illegalMerchantId':
                $title = '非法访问';
                $msg = '您访问的数据出现异常，可能此数据并非是您的商家数据!';
                break;

            case 'illegalData':
                $title = '数据出错';
                $msg = '您访问的数据出现异常，系统无法正常运行!';
                break;
        }
        return $this->render('error', ['title'=>$title, 'msg'=>$msg]);
    }
}