timeStampToHour method
Implementation
int? timeStampToHour() {
//如果是十三位时间戳返回这个
var timeStamp = this;
if (toString().length == 13) {
timeStamp = DateTime.fromMillisecondsSinceEpoch(timeStamp).hour;
} else if (toString().length == 16) {
//如果是十六位时间戳
timeStamp = DateTime.fromMicrosecondsSinceEpoch(timeStamp).hour;
}
return timeStamp;
}