文件下载

public function show($path, $ext, $name) {
    if ($ext == 'pdf') {
        header("Pragma: no-cache");
        header("Cache-Control: no-cache, must-revalidate");
        header('Content-type: application/pdf');
        header('Content-Disposition: attachment; filename=' . "$name");
        readfile($path);
    }elseif ($ext == 'doc' || $ext == 'docx') {
        header("Pragma: no-cache");
        header("Cache-Control: no-cache, must-revalidate");
        header('Content-type: application/msword');
        header('Content-Disposition: attachment; filename=' . "$name");
        readfile($path);
    }elseif ($ext == 'xls' || $ext == 'xlsx') {
        header("Pragma: no-cache");
        header("Cache-Control: no-cache, must-revalidate");
        header('Content-type: application/vnd.ms-excel');
        header('Content-Disposition: attachment; filename=' . "$name");
        readfile($path);
    }
}