phonebook/web/index.php

<?php

// comment out the following two lines when deployed to production
defined('YII_DEBUG') or define('YII_DEBUG', true);//定義兩個常量，查看你當前是運行環境還是開發環境
defined('YII_ENV') or define('YII_ENV', 'dev');

require __DIR__ . '/../vendor/autoload.php';
require __DIR__ . '/../vendor/yiisoft/yii2/Yii.php';

$config = require __DIR__ . '/../config/web.php';

(new yii\web\Application($config))->run();