Symfony 下载文件不存在

我使用admin文件夹构建csv导出。该文件已上载到我的公用文件夹中。 但是，当我尝试使用return下载时，出现了一个错误：

文件“/public/exportCSV.csv”不存在

我不明白为什么，我希望你有个主意。谢谢我在四号线以下

    $admins = $userRepository->findByRole(User::ROLE_ADMIN);
    $filename='exportCSV';
    $extension='csv';


    $request = Request::createFromGlobals();
    if($request->query->get('exportCSV')!= null){

        $output = fopen($filename.'.'.$extension, 'w');
        fputcsv($output, array("Id","Nom","Prénom","Activé","Dernière connexion","Date d'inscription","Url avatar","Email","Username"));
        foreach ($admins as $admin){
            $id=$admin->getId();
            $lastname=$admin->getLastName();
            $firstname=$admin->getFirstName();
            $activeState=$admin->getActiveState();
            if($activeState){
                $active='Oui';
            }else{
                $active='Non';
            }
            $lastConnectedAt=$admin->getLastConnected();
            if($lastConnectedAt==null){
                $lastConnected=" ";
            }else{
                $lastConnected=$lastConnectedAt->format('Y-m-d H:i:s');
            }
            $createdAt=$admin->getCreatedAt();
            if($createdAt==null){
                $created=" ";
            }else{
                $created=$createdAt->format('Y-m-d H:i:s');
            }
            $urlAvatar=$admin->getUrlAvatar();
            $mail=$admin->getEmail();
            $username=$admin->getUsername();

            $csvLine= array($id,$lastname,$firstname,$active,$lastConnected,$created,$urlAvatar,$mail,$username);
            fputcsv($output,$csvLine);
        }
        return $this->file('/public/'.$filename.'.'.$extension);

    }

---

您必须使用Web服务器“public”目录的正确路径。检查

在你的例子中，你可以像这样做

 $publicDir = $this->getParameter('kernel.project_dir') . '/public/'; # Your controller must extend AbstractController
 $output = fopen($publicDir . $filename.'.'.$extension, 'w');