``` //从全局静态变量里取出response组件 $response=\YII::$app->response; //设置状态码 //$response->statusCode='404'; //$response->headers->add('pragma','no-cache'); //$response->headers->set('pragma','max-age=5'); //$response->headers->remove('pragma'); //跳转 //$response->headers->add('location','http://www.baidu.com'); //$response->redirect('http://www.baidu.com'); //文件下载 //$response->headers->add('content-disposition','attachment;filename="a.jpg"'); $response->sendFile('./robots.txt'); //echo $response->version; ```