其实非常简单利用date()函数一行代码搞定.
封了个函数放在github上, [链接:https://github.com/miracle2017/code_snippet/blob/c81976d3251170de1cd54db2e14def9d66431b6b/code.php#L56](https://github.com/miracle2017/code_snippet/blob/c81976d3251170de1cd54db2e14def9d66431b6b/code.php#L56)

(from my blog: https://blog.nice100.net/php/134.html)