Yii2 连接多个数据库

'components' => [
    'db' => [
        'class' => 'yii\db\Connection',
        'dsn' => 'mysql:host=localhost;dbname=test',
        'username' => '***',
        'password' => '**',
        'charset' => 'utf8',
    ],
    'db2' => [
        'class' => 'yii\db\Connection',
        'dsn' => 'mysql:host=localhost;dbname=test2',
        'username' => '***',
        'password' => '***',
        'charset' => 'utf8',
    ],
    'mailer' => [
        'class' => 'yii\swiftmailer\Mailer',
        'viewPath' => '@common/mail',
        // send all mails to a file by default. You have to set
        // 'useFileTransport' to false and configure a transport
        // for the mailer to send real emails.
        'useFileTransport' => true,
    ],
],

namespace app\models;

use Yii;

/**
 * This is the model class for table "test2".
 *
 * @property int $id
 * @property string $name
 */
class Test2 extends \yii\db\ActiveRecord
{
    /**
     * {@inheritdoc}
     */
    public static function tableName()
    {
        return 'test2';
    }

    /**
     * @return \yii\db\Connection the database connection used by this AR class.
     */
    public static function getDb()
    {
        return Yii::$app->get('db2');
    }

    /**
     * {@inheritdoc}
     */
    public function rules()
    {
        return [
            [['name'], 'string', 'max' => 60],
        ];
    }

    /**
     * {@inheritdoc}
     */
    public function attributeLabels()
    {
        return [
            'id' => '编号',
            'name' => '姓名',
        ];
    }
}

Test::find()->all();