How to validate the Currency String in java

Question

Suppose I have a currency String in German format:

String money="1.203.432,25";

I want to check if money is a valid currency value. "0,00" is valid, "134.20,24" is invalid, "02,23" is invalid and so on. How can I do it in Java?

Why is "02,23" invalid? That's about the cost in Euros of an espresso at a German railway station. — Bathsheba, Oct 01 '15 at 12:52

Thomas · Answer 1 · 2015-10-01T13:38:39.973

2

Use a localized number format (or a regex if it's always in German format).

Regex could be something like ^(?:0|[1-9][0-9]{0,2}(?:\.[0-9]{3})*),[0-9]{2}$, with ^ and $ not being necessary when using String#matches() or Matcher#matches().

Number format could be a DecimalFormat like ###,##0.00 or just use NumberFormat.getInstance( Locale.GERMAN ). The problem with number formats, however, is that it allows a number to have leading zeros so if you want to disallow those you could check the first digit for being a zero or not.

edited Oct 01 '15 at 13:38

answered Oct 01 '15 at 12:50

Thomas

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NumberFormat didn't work, as it allowed e.g. leading zeros RegExp should it be, I think, just looking for the right now. – Alexei Vinogradov Oct 01 '15 at 13:24
Looks like that ^(?:0|[1-9]\d{0,2}(?:\.\d{3})*),\d{2}$ does the trick – Alexei Vinogradov Oct 01 '15 at 13:33
1

@AlexeiVinogradov yes, that seems to be ok (I'll add that `0,xx` case to the answer for others to spot). Just note that `\d` would allow foreign digits as well so you might want to use `[0-9]` instead. – Thomas Oct 01 '15 at 13:35

SWoeste · Answer 2 · 2015-10-01T13:40:32.350

0

Maybe the Apache CurrencyValidator is what you are looking for.

public static void main (String[] args) throws java.lang.Exception {
     BigDecimalValidator validator = CurrencyValidator.getInstance();

     BigDecimal amount = validator.validate("€ 123,00", Locale.GERMAN);

     if(amount == null){
         System.out.println("Invalid amount/currency.");
     }

}

edited Oct 01 '15 at 13:40

answered Oct 01 '15 at 13:05

SWoeste

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Have you tested it with "023,00€"? – Alexei Vinogradov Oct 01 '15 at 13:31
The leading zero is accepted, so it does not work for your case -sorry. – SWoeste Oct 01 '15 at 13:38

score 0 · Accepted Answer · edited Aug 15 '22 at 15:11

0

This snippet seems to work:

String money="23.234,00";
Pattern p=Pattern.compile("^(?:0|[1-9]\\d{0,2}(?:\\.\\d{3})*),\\d{2}$");
Matcher m=p.matcher(money);
if (m.matches()) System.out.println("valid");
else System.out.println("invalid");

edited Aug 15 '22 at 15:11

smilyface

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answered Oct 01 '15 at 13:46

Alexei Vinogradov

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Side note: `Matcher.find()` would look for multiple occurences if you leave out `^` and `$`. Using `Matcher.matches()` would do the same and try to match the _entire_ input string. – Thomas Oct 01 '15 at 13:49
Invalid for `0.1` – smilyface Aug 15 '22 at 15:14
0.1 is not a valid German currency value – Alexei Vinogradov Oct 18 '22 at 16:31

score 0 · Answer 4 · answered Oct 28 '18 at 11:56

0

Use the following Pattern: "([0-9]{1,3}\.)*[0-9]{1,3}\,[0-9]{2}"

System.out.println("11.118.576.587,58".matches("([0-9]{1,3}\\.)*[0-9]{1,3}\\,[0-9]{2}"));

answered Oct 28 '18 at 11:56

J. Jerez

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How to validate the Currency String in java

4 Answers4