检出php.ini，为session设置的值.gc_maxlifetime是ID生存时间(以秒为单位).

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

我相信默认值为1440秒(24分钟)

I believe the default is 1440 seconds (24 mins)

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

编辑:正如一些评论所指出的那样，上述内容并不完全正确.有关为什么以及如何实现会话生存期的精彩说明可在此处找到:

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分钟后使PHP会话到期分钟?