查看 php.ini 为 session.gc_maxlifetime 设置的值是 ID 生命周期，单位为秒.

Check out php.ini the value set for session.gc_maxlifetime is the ID lifetime in seconds.

我相信默认值是 1440 秒(24 分钟)

I believe the default is 1440 seconds (24 mins)

http://www.php.net/manual/en/session.配置.php

正如一些评论指出的那样，上述内容并不完全准确.此处提供了有关为什么以及如何实现会话生存期的精彩解释:

As some comments point out, the above is not entirely accurate. A wonderful explanation of why, and how to implement session lifetimes is available here:

如何在 30 后过期 PHP 会话分钟?