I want a function to convert Bigdecimal 10.12 for 10.12345
and 10.13 for 10.12556
.
But no function is satisfying both conversion in same time.Please help to achieve this.
Below is what I tried.
With value 10.12345:
BigDecimal a = new BigDecimal("10.12345");
a.setScale(2, BigDecimal.ROUND_UP)
a.setScale(2, BigDecimal.ROUND_CEILING)
a.setScale(2, BigDecimal.ROUND_DOWN)
a.setScale(2, BigDecimal.ROUND_FLOOR)
a.setScale(2, BigDecimal.ROUND_HALF_DOWN)
a.setScale(2, BigDecimal.ROUND_HALF_EVEN)
a.setScale(2, BigDecimal.ROUND_HALF_UP)
Output :
10.12345::10.13
10.12345::10.13
10.12345::10.12
10.12345::10.12
10.12345::10.12
10.12345::10.12
10.12345::10.12
With value 10.12556:
BigDecimal b = new BigDecimal("10.12556");
b.setScale(2, BigDecimal.ROUND_UP)
b.setScale(2, BigDecimal.ROUND_CEILING)
b.setScale(2, BigDecimal.ROUND_DOWN)
b.setScale(2, BigDecimal.ROUND_FLOOR)
b.setScale(2, BigDecimal.ROUND_HALF_DOWN)
b.setScale(2, BigDecimal.ROUND_HALF_EVEN)
b.setScale(2, BigDecimal.ROUND_HALF_UP)
Output :
10.12556::10.13
10.12556::10.13
10.12556::10.12
10.12556::10.12
10.12556::10.12
10.12556::10.12
10.12556::10.12
I think that the RoundingMode
you are looking for is HALF_EVEN
. From the javadoc:
Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor. Behaves as for ROUND_HALF_UP if the digit to the left of the discarded fraction is odd; behaves as for ROUND_HALF_DOWN if it's even. Note that this is the rounding mode that minimizes cumulative error when applied repeatedly over a sequence of calculations.
Here is a quick test case:
BigDecimal a = new BigDecimal("10.12345");
BigDecimal b = new BigDecimal("10.12556");
a = a.setScale(2, RoundingMode.HALF_EVEN);
b = b.setScale(2, RoundingMode.HALF_EVEN);
System.out.println(a);
System.out.println(b);
Correctly prints:
10.12
10.13
UPDATE:
setScale(int, int)
has not been recommended since Java 1.5, when enums were first introduced, and was finally deprecated in Java 9. You should now use setScale(int, RoundingMode)
e.g:
setScale(2, RoundingMode.HALF_EVEN)