Joda Time 取整天的方法

DateTime now = new DateTime(); // 2023-02-26T16:51:28.749+08:00
now.dayOfWeek().roundCeilingCopy(); // 2023-02-27T00:00:00.000+08:00
now.dayOfWeek().roundFloorCopy(); // 2023-02-26T00:00:00.000+08:00
now.minuteOfDay().roundFloorCopy(); // 2023-02-26T16:51:00.000+08:00
now.secondOfMinute().roundFloorCopy(); // 2023-02-26T16:51:28.000+08:00