52

How to convert from float to bigDecimal in java?

mskfisher
  • 3,177
  • 3
  • 33
  • 47
akp
  • 1,733
  • 7
  • 25
  • 29

4 Answers4

66
BigDecimal value = new BigDecimal(Float.toString(123.4f));

From the javadocs, the string constructor is generally the preferred way to convert a float into a BigDecimal, as it doesn't suffer from the unpredictability of the BigDecimal(double) constructor.

Quote from the docs:

Note: For values other float and double NaN and ±Infinity, this constructor is compatible with the values returned by Float.toString(float) and Double.toString(double). This is generally the preferred way to convert a float or double into a BigDecimal, as it doesn't suffer from the unpredictability of the BigDecimal(double) constructor.

aioobe
  • 399,198
  • 105
  • 792
  • 807
dogbane
  • 254,755
  • 72
  • 386
  • 405
  • 7
    But converting a `float` to a String explicitly doesn't help you solve the unpredictability automatically - you need to take care to format the value correctly (rounding etc.). – Jesper Sep 30 '10 at 08:58
  • How to convert and format 9.991f to 910 and 9.99f to 9.99? – Jobin Aug 10 '21 at 08:45
24
float f = 45.6f;
BigDecimal bd = BigDecimal.valueOf(f);

Quote from documentations:

Note: This is generally the preferred way to convert a double (or float) into a BigDecimal, as the value returned is equal to that resulting from constructing a BigDecimal from the result of using Double.toString(double).

Reference: BigDecimal (Java Platform SE 6)

Spacemonkey
  • 1,653
  • 3
  • 19
  • 43
8

For a precision of 3 digits after the decimal point:

BigDecimal value = new BigDecimal(f,
        new MathContext(3, RoundingMode.HALF_EVEN));
Maurice Perry
  • 32,157
  • 9
  • 69
  • 96
2

This is upto my knowledge :

   public static BigDecimal floatToBigDecimal(Float a){


    if(a == null || a.isInfinite() || a.isNaN()){
        return BigDecimal.ZERO;
    }
    try{
        return BigDecimal.valueOf(a);

    }catch(Exception e){
        return BigDecimal.ZERO;
    }

}

*Note:This is generally the preferred way to convert a double (or float) into a BigDecimal, as the value returned is equal to that resulting from constructing a BigDecimal from the result of using Double.toString(double).

public static BigDecimal valueOf(double val)

Parameters:
val - double to convert to a BigDecimal.
Returns:
a BigDecimal whose value is equal to or approximately equal to the value of val.
Throws:
NumberFormatException - if val is infinite or NaN.
Since:
1.5

I have checked whether Infinite or Not a Number, so that there is less chances of NumberFormatException