Java十进制格式问题零（0.00）

Question

I have a problem with the formatter, when I give a 0.00 return +0,00 E but I would like to 0,00 E.

String PATTERN = "###,##0.00\u00a0\u00A4";
DecimalFormatSymbols SYMBOLS = DecimalFormatSymbols.getInstance(Locale.FRANCE);
DecimalFormat FORMATTER_SIGN = new DecimalFormat(PATTERN, SYMBOLS);
FORMATTER_SIGN.setNegativePrefix("-\u00a0");
FORMATTER_SIGN.setPositivePrefix("+\u00a0");
FORMATTER_SIGN.format("0.00") // this

Answer 1

I can get rid of the "+" when I remove the line

FORMATTER_SIGN.setPositivePrefix("+\u00a0");

or change it to

FORMATTER_SIGN.setPositivePrefix("");

Resulting in

0,00 €

PS: Your format call doesn't work for me, I need to do something like this:

FORMATTER_SIGN.format(Double.valueOf("0.00")); // this

Answer 2

You could create your own DecimalFormat that is aware of zeros (simplified example):

class ZeroAwareDecimalFormat extends DecimalFormat {
    private final DecimalFormat zeroFormat;

    public ZeroAwareDecimalFormat(String posNegPattern, String zeroPattern) {
        super(posNegPattern);
        zeroFormat = new DecimalFormat(zeroPattern);
    }

    @Override
    public StringBuffer format(long number, StringBuffer result, FieldPosition fieldPosition) {
        if (number == 0L) {
            return zeroFormat.format(number, result, fieldPosition);
        } else {
            return super.format(number, result, fieldPosition);
        }
    }

    // Override the other methods accordingly.
    // set... methods should be propagated to super and zeroFormat.
}