How to make strings from floating-point numbers with '.' (dot) as a decimal separator and not more than 3 digits after floating point?

问题

I have this code:

public String formatDouble(double d) {
   return String.format("???", d); //Should I use NumberFormat here?
}

For the sample input:

1.00
1,00
1,23
1.234567

I would like to get this output:

1
1
1.23
1.234

How can I configure the pattern (or maybe NumberFormat instance) for producing the correct output?

回答1:

This would do roughly what you need:

Decimalformat df = new DecimalFormat("0.###");
df.setRoundingMode(RoundingMode.FLOOR);
df.format(1.2345);

However, the decimal separator (the dot) will be dependent on current locale. To override it, you may want to provide your own format symbols (see DecimalFormat.setDecimalFormatSymbols()).

回答2:

DecimalFormat should do what you need.

回答3:

Simple way: String.format("%.2f", 1234.23)

If you need thousand separator, add a comma before the dot: String.format("%,.2f", 1234.23) -> the result: 1,234.23.

来源：https://stackoverflow.com/questions/8712504/how-to-make-strings-from-floating-point-numbers-with-dot-as-a-decimal-sepa