BigDecimal不整除的一个异常java.lang.ArithmeticException: Non-terminating decimal expansion

 金额的数据类型是BigDecimal
通过BigDecimal的divide方法进行除法时当不整除,出现无限循环小数时,就会抛异常的,异常如下:java.lang.ArithmeticException:

 Non-terminating decimal expansion; no exact representable decimal result. at java.math.BigDecimal.divide(Unknown Source)

应用场景:一批中供客户的单价是1000元/年,如果按月计算的话1000/12=83.3333333333....

解决之道:就是给divide设置精确的小数点divide(xxxxx,2, BigDecimal.ROUND_HALF_EVEN)

在 java中, 四舍五入通过 BigDecimal 来实现。一定要注意:BigDecimal is Immutable。

也就是跟String一样,对前一个的修改,比如setScale(), add()等都会返回一个新的BigDecimal.

四舍五入舍入模式是 BigDecimal.ROUND_HALF_UP 

BigDecimal定义了一下舍入模式,只有在作除法运算或四舍五入时才用到舍入模式,

下面简单介绍,详细请查阅J2se API文档

 

static int

ROUND_CEILING

Rounding mode to round towards positive infinity.

向正无穷方向舍入

static int

ROUND_DOWN

Rounding mode to round towards zero.

向零方向舍入

static int

ROUND_FLOOR

Rounding mode to round towards negative infinity.

向负无穷方向舍入

static int

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

static int

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

static int

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

static int

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

static int

ROUND_UP

Rounding mode to round away from zero.

向远离0的方向舍入


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