Java Currency Number format

Question

Hi, Is there a way to format a decimal as following:

100 -> "100" 100.1 -> "100.10"

i.e. if it is round omit the decimal part otherwise always show 2dp.

Thxs.

Answer 1

Yes. You can use java.util.formatter. You can use a formatting string like "%10.2f"

Answer 2

you should do something like this:

public static void main(String[] args) {
    double d1 = 100d;
    double d2 = 100.1d;
    print(d1);
    print(d2);
}

private static void print(double d) {
    String s = null;
    if (Math.round(d) != d) {
        s = String.format("%.2f", d);
    } else {
        s = String.format("%.0f", d);
    }
    System.out.println(s);
}

which prints:

100

100,10

Answer 3

I doubt it. The problem is that 100 is never 100 if it's a float, it's normally 99.9999999999 or 100.0000001 or something like that.

If you do want to format it that way, you have to define an epsilon, that is, a maximum distance from an integer number, and use integer formatting if the difference is smaller, and a float otherwise.

Something like this would do the trick:

public String formatDecimal(float number) {
  float epsilon = 0.004; // 4 tenths of a cent
  if ( abs(Math.round(number) - number) < epsilon) {
     return String.format("%10.0f", number); // sdb
  } else {
     return String.format("%10.2f", number); // dj_segfault
  }
}

Answer 4

I'd recommend using the java.text package:

double money = 100.1;
NumberFormat formatter = NumberFormat.getCurrencyInstance();
System.out.println(formatter.format(money));

This has the added benefit of being locale specific.