How to use Java's DecimalFormat for “smart” currency formatting?

Question

I\'d like to use Java\'s DecimalFormat to format doubles like so:

#1 - 100 -> $100
#2 - 100.5 -> $100.50
#3 - 100.41 -> $100.41

Th

Answer 1

You can check "is number whole or not" and choose needed number format.

public class test {

  public static void main(String[] args){
    System.out.println(function(100d));
    System.out.println(function(100.5d));
    System.out.println(function(100.42d));
  }

  public static String function(Double doubleValue){
    boolean isWholeNumber=(doubleValue == Math.round(doubleValue));
    DecimalFormatSymbols formatSymbols = new DecimalFormatSymbols(Locale.GERMAN);
    formatSymbols.setDecimalSeparator('.');

    String pattern= isWholeNumber ? "#.##" : "#.00";    
    DecimalFormat df = new DecimalFormat(pattern, formatSymbols);
    return df.format(doubleValue);
  }
}

will give exactly what you want:

100
100.50
100.42