NumberFormatException for input string: "15,7"

Question

I am getting a NumberFormatException when trying to parse a number such as "15,7". This would be "15.7" in US or UK format. I've attempted to retrieve the locale from the PC and parse based on that, as follows:

if (strCountry.equals("IT")) {
    locale = java.util.Locale.ITALIAN;
} else {
    locale = java.util.Locale.ENGLISH;
}

NumberFormat m_nf = NumberFormat.getInstance(locale);
m_nf.setMaximumFractionDigits(1);

From logging I've confirmed that the system returns "IT" as the country. The parsing is then attempted like this:

Double nCount = new Double(m_nf.format(total_ff));

However this is where the exception is thrown, due to a comma being used as a decimal point. Have I missed something? Thanks!

It depends on what your trying to do with it. But yes, you should be working with floating. To see if javascript is seeing the value like it should you can always use typeof. It will return the type of number it is interpreted as. — MadeInDreams, Dec 18 '16 at 22:34

score 3 · Accepted Answer · answered Dec 18 '16 at 22:41

3

I think you mix format() and parse() methods.

public final String format(double number)

takes as parameter a number and returns a String.

public Number parse(String source) throws ParseException

takes as parameter a String and return a number.

In your case, you have a String in a specific locale format and you want to retrieve the numeric value. So you should use parse() and not format().

Here is an example :

public static void main(String[] args) throws ParseException {
  Locale locale = java.util.Locale.ITALIAN;
  String valueString = "15,7";
  NumberFormat m_nf = NumberFormat.getInstance(locale);
  m_nf.setMaximumFractionDigits(1);
  Double number = (Double) m_nf.parse(valueString);
}

answered Dec 18 '16 at 22:41

davidxxx

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If I had mixed them up wouldn't I receive a compile-time error? The variable in my example (`total_ff`) is of type `Double`. Confused as to why it says it's a string in the exception though... – petehallw Dec 19 '16 at 08:43
Because these are two distinct things. The risen exception is not related to the `parse()` method call. The problem happens in the `Double` constructor invocation : `Double nCount = new Double("15,7");` which rises the exception. `Double nCount = new Double("15.7");` works. I said you mix because you format a `Double` as a `String` in a specific Locale format and you use this `String` to instantiate a `Double`. You should not do it since the `Double` constructor is independent of the `Locale`. Also, just an advise : the next time you should post all required code. It eases the understanding. – davidxxx Dec 19 '16 at 11:31

Rob Pridham · Answer 2 · 2016-12-18T22:48:32.623

0

Try this, or a variation thereof:

DecimalFormatSymbols symbols = DecimalFormatSymbols.getInstance(locale);
DecimalFormat format = new DecimalFormat("#.0", symbols);
Double nCount = (Double) format.parse(total_ff);

Edit: corrected to parse as per other people's answers!

edited Dec 18 '16 at 22:48

answered Dec 18 '16 at 22:34

Rob Pridham

4,780
1
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38

NumberFormatException for input string: "15,7"

2 Answers2