由于业务需求,要计算客户今日收益,本周本月,本年等收益, 1.查询当天0点0分0秒 2.查询本月一号0点0分0秒 ...... Calendar calendar = Calendar.getInstance();calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), calendar.get(Calendar.DAY_OF_MONTH), 0, 0, 0);Calendar calendar2 = Cale