周相关

//获取星期一
localDate.with(DayOfWeek.MONDAY)
//下周星期一
localDate.with(TemporalAdjusters.next(DayOfWeek.MONDAY))

月相关

//月初日期
localDate.with(TemporalAdjusters.firstDayOfMonth())
//月末日期
localDate.with(TemporalAdjusters.lastDayOfMonth())

年相关

//年第一天
localDate.with(TemporalAdjusters.firstDayOfYear())
//年最后一天
localDate.with(TemporalAdjusters.lastDayOfYear())

Q.E.D.