PHP里的“夏令虫”
今儿,我遇到一个大怪物 -- 夏令虫
╮(╯▽╰)╭,学艺不精,因为他掉进大坑里去了。坑是这样挖的:
以前,我为了表示当前时间的“明天”、“后天”,会用到类如下面的写法:
$date = date(time + 3600*24*N);
殊不知,这种写法并不安全的,请看例子:
ini_set('date.timezone','Europe/Berlin'); echo date("Y-m-d H:i:s",1382824800); echo "<br/>"; echo date("Y-m-d H:i:s",1382824800 + 1*86400); ini_set('date.timezone','Europe/Berlin'); echo date("Y-m-d H:i:s",1382824800); echo "<br/>"; echo date("Y-m-d H:i:s",1382824800 + 1*86400);
输出的结果是
2013-10-27 00:00:00 2013-10-27 23:00:00 2013-10-27 00:00:00 2013-10-27 23:00:00
第二天被偷偷吃掉一个小时!
而且未来154天都会这样,直到第155天,这一小时才会“被还回来”。
为什么会这个样子?通过查询资料发现,原来是夏令时导致的问题,
不过,我国当前未实行夏令时,所以,这个问题对于“Asia/Shanghai”来说,暂时不会成为问题。
关于日期的格式化,还是推荐寻找使用更科学的计算方式。
以前写的PHP代码都有可能会因此而BUG,在这里向以前的项目致歉了。

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