日期格式如下：2020-09-25 00:00:00，并且中间-是可以省略的，那么我们到了后台就需要将时间给转换回来
^((\d{2}(([02468][048])|([13579][26]))[\-]?((((0[13578])|(1[02]))[\-]?((0[1-9])|([1-2][0-9])|(3[01])))|(((0[469])|(11))[\-]?((0[1-9])|([1-2][0-9])|(30)))|(02[\-]?((0[1-9])|([1-2][0-9])))))|(\d{2}(([02468][1235679])|([13579][01345789]))[\-]?((((0[13578])|(1[02]))[\-]?((0[1-9])|([1-2][0-9])|(3[01])))|(((0[469])|(11))[\-]?((0[1-9])|([1-2][0-9])|(30)))|(02[\-]?((0[1-9])|(1[0-9])|(2[0-8])))))) (((([0-1][0-9])|(2[0-3]))[\:]?([0-5][0-9])[\:]?((([0-5][0-9])))))$
public static String standardDatetime(String datetime) {if (datetime.charAt(4) != '-') {datetime = datetime.substring(0, 4) + "-" + datetime.substring(4, datetime.length());}if (datetime.charAt(7) != '-') {datetime = datetime.substring(0, 7) + "-" + datetime.substring(7, datetime.length());}if (datetime.charAt(13) != ':') {datetime = datetime.substring(0, 13) + ":" + datetime.substring(13, datetime.length());}if (datetime.charAt(16) != ':') {datetime = datetime.substring(0, 16) + ":" + datetime.substring(16, datetime.length());}return datetime;}
)
