Java String.format with currency symbol

Question

There is some existing code of the follow form which is used for format numerical values:

String.format( pattern, value )

Answer 1

No need to reinvent the wheel. DecimalFormat comes with currency support:

String output = DecimalFormat.getCurrencyInstance().format(123.45);

This also comes with full locale support by optionally passing in a Locale:

String output = DecimalFormat.getCurrencyInstance(Locale.GERMANY).format( 123.45);

Here's a test:

System.out.println(DecimalFormat.getCurrencyInstance().format( 123.45) );
System.out.println(DecimalFormat.getCurrencyInstance(Locale.GERMANY).format( 123.45)) ;

Output:

$123.45
123,45 €

Answer 2

If there is no default Locale available, we can go with setting the currency symbol using unicode and decimal formatting. As in the below code:

For e.g. Setting the Indian currency symbol and formatting the value. This will work without user making changes in the settings.

Locale locale = new Locale("en","IN");
DecimalFormat decimalFormat = (DecimalFormat) DecimalFormat.getCurrencyInstance(locale);
DecimalFormatSymbols dfs = DecimalFormatSymbols.getInstance(locale);
dfs.setCurrencySymbol("\u20B9");
decimalFormat.setDecimalFormatSymbols(dfs);
System.out.println(decimalFormat.format(12324.13));

Output:

₹12,324.13

Answer 3

    String formatstring=String.format("$%s", 123);
    System.out.println(formatstring);

Answer 4

With the constraints you have given, I think it is impossible to achieve it. To get to the current Locale's currency symbol, you'll need a minimum of code.

If you have absolutely no means to add code to the program, you'd best use the established symbol for "currency" (¤). It was established for this exact purpose, to symbolize currency absent any more specific symbol.

If you can't change the given code, but add code to the project as a whole, you can use that to find out the symbol best used. Once you have it, you can use it to create a pattern for the existing code to use for formatting.

If you can find out in which Locale the original program will run in next, you could write a assistant program that uses that setting to fill your configuration.

Answer 5

You can try the following:

public static void main(String[] args) {
    System.out.println(String.format(" %d \u20AC", 123)); // %d for integer
    System.out.println(String.format(" %.2f \u20AC", 123.10)); // %f for floats
}

This prints:

123 €
123.10 €