1、标准版,保留两位,不会四舍五入
DecimalFormat formater = new DecimalFormat(); formater.setMaximumFractionDigits(2); formater.setGroupingSize(0); formater.setRoundingMode(RoundingMode.FLOOR); double aaa = 12.3456; String result = formater.format(aaa); //输出结果为12.34 DecimalFormat formater = new Dec