case 'xiazai':     if (isset($_GET['url'])) {     $path =trim(urldecode($_GET['url']));     if(!in_array($x->get_file_ext($path),explode(',', $conf['download_ext']))){     die("不允许下载的文件类型!");     }     header('Content-Type: application/octet-stream');     header("Content-Disposition: attachment; filename=\"" . basename($path) . "\"");     header("Content-Length: " . filesize($path));     readfile($path); }          break; 应该是没有吧，我就是这样设置的