第一段是读文件，下载。

第二段是字符串下载。

复制代码 代码如下:

<?php

$fileName = "prefs.csv";

header('Content-Type: application/octet-stream');

header('Content-Disposition: attachment; filename=' . $fileName);

header('Content-Transfer-Encoding: binary');

header('Content-Length: ' . filesize($fileName));

readfile($fileName);

复制代码 代码如下:

<?php

$fileName = "pref_" . date("YmdHis") . ".csv";

header('Content-Type: application/octet-stream');

header('Content-Disposition: attachment; filename=' . $fileName);

echo $csv;