yii2怎么设置切换语言

'components' => [
        'i18n' => [
            'translations' => [
                '*' => [
                    'class' => 'yii\i18n\PhpMessageSource',
                    //'basePath' => '/messages',
                    'fileMap' => [
                        'app' => 'app.php',
                    ],
                ],
            ],
        ],
]

<?php
return [
    //常用
    'Action' => '操作',
    'Search' => '搜索',
    'Reset' => '重置',
];

$application = new yii\web\Application($config);
$application->language = isset(\Yii::$app->session['language']) ? \Yii::$app->session['language'] : 'en';
$application->run();

public function actionLanguage(){       
    $language=  \Yii::$app->request->get('lang');  
    if(isset($language)){  
        \Yii::$app->session['language']=$language;  
    }  
    //切换完语言哪来的返回到哪里
    $this->goBack(\Yii::$app->request->headers['Referer']);  
}