How to add dot in between numbers using java

Question

I need to validate customer entered input with java. ie we should allow numbers seven digits, after that if customer willing to enter numbers we should add '.' (dot) as separator.After separator we should allow only two digits, if any more digits enter we should throw an error.

Ex: 12345 --> Valid

Thanks,

Answer 1

You can use regular expressions for that:

private static final String PATTERN = "\\d{1,7}(\\.\\d{1,2})?";

public static void main(final String[] args) {
    final Pattern ptrn = Pattern.compile(PATTERN);
    System.out.println(ptrn.matcher("1").matches());
    System.out.println(ptrn.matcher("1234567").matches());
    System.out.println(ptrn.matcher("12345678").matches());
    System.out.println(ptrn.matcher("1234567.").matches());
    System.out.println(ptrn.matcher("1234567.1").matches());
    System.out.println(ptrn.matcher("1234567.12").matches());
    System.out.println(ptrn.matcher("1234567.123").matches());
    System.out.println(ptrn.matcher("1.12").matches());
    System.out.println(ptrn.matcher(".12").matches());
}