tp5下载文件

public function getDemo(Request $request){
         $file = '/static/file/demo.xlsx';
         //str_replace为了严谨点嘛，不要也可以
         $file_lj = str_replace("\\","/",ROOT_PATH.'public');
         $files = $file_lj.$file;

         if(!file_exists($files)){
             return "文件不存在";
         }else {
             //打开文件
             $file1 = fopen($files, "r");
             //输入文件标签
             Header("Content-type: application/octet-stream");
             Header("Accept-Ranges: bytes");
             Header("Accept-Length: " . filesize($files));
             Header("Content-Disposition: attachment; filename=demo.xlsx");
             echo fread($file1, filesize($files));
             fclose($file1);
         }



    }