//返回響應(yīng)組件
$res = \YII::$app->response;
//設(shè)置返回瀏覽器狀態(tài)碼
$res->statusCode='404';
//設(shè)置http頭
$res->headers->add('pragma','no-cache');
$res->headers->set('pragma','no-cache');
$res->headers->remove('pragma');
//跳轉(zhuǎn)
$res->headers->add('Location','www.baidu.com');
$res->redirect('www.baidu.com','302');
//文件下載
$res>headers>add('contentdisposition','www.baidu.com');
 $res->sendFile('./robots.txt');