bigdecimal 保留小数位
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public class test1_format { public static void main(String[] args) { BigDecimal decimal = new BigDecimal("1.12345"); System.out.println(decimal); BigDecimal setScale = decimal.setScale(4,BigDecimal.ROUND_HALF_DOWN); System.out.println(setScale); BigDecimal setScale1 = decimal.setScale(4,BigDecimal.ROUND_HALF_UP); System.out.println(setScale1); } } |
参数定义
ROUND_CEILING
Rounding mode to round towards positive infinity.
向正无穷方向舍入
ROUND_DOWN
Rounding mode to round towards zero.
向零方向舍入
ROUND_FLOOR
Rounding mode to round towards negative infinity.
向负无穷方向舍入
ROUND_HALF_DOWN
Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down.
向（距离）最近的一边舍入，除非两边（的距离）是相等,如果是这样，向下舍入, 例如1.55 保留一位小数结果为1.5
ROUND_HALF_EVEN
Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor.
向（距离）最近的一边舍入，除非两边（的距离）是相等,如果是这样，如果保留位数是奇数，使用ROUND_HALF_UP ，如果是偶数，使用ROUND_HALF_DOWN
ROUND_HALF_UP
Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up.
向（距离）最近的一边舍入，除非两边（的距离）是相等,如果是这样，向上舍入, 1.55保留一位小数结果为1.6
ROUND_UNNECESSARY
Rounding mode to assert that the requested operation has an exact result, hence no rounding is necessary.
计算结果是精确的，不需要舍入模式
ROUND_UP
Rounding mode to round away from zero.
向远离0的方向舍入
from:https://www.cnblogs.com/liqforstudy/p/5652517.html