Question

All in the title.., I’m looking for a safe way to format all Double in this manner, some other examples:

1000 ==> 1.000

1500 ==> 1.500

22000 ==> 22.000

1555005 ==> 1 555.005

I have looked in this link but not helped…

there is a safe way to do that ? THX in advance

Answer 1

You want to print your input number divided by a thousand, using a decimal dot and space as thousand separator. The safe way is to first convert to BigDecimal, scale by 10^-3, then print it using DecimalFormat.

final DecimalFormat f = new DecimalFormat("#,###.000");
final DecimalFormatSymbols s = new DecimalFormatSymbols();
s.setGroupingSeparator(' ');
s.setDecimalSeparator('.');
f.setDecimalFormatSymbols(s);
final double input = 1_555_005;
final BigDecimal x = new BigDecimal(input).scaleByPowerOfTen(-3);
System.out.println(f.format(x));

prints

1 555.005

Note that setting grouping/decimal separators explicitly like here is not the orthodox way to do this: normally you would let the Locale setting dictate the number format.