Question

I am using the following code to validate date entered in edittextbox.however in xml file I had given its input type date.

int i = validate(registerdate);

this is validate function:

private int  validate(String registerdate) {

        String regEx =
            "^(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\d\d$";
          Matcher matcherObj = Pattern.compile(regEx).matcher(registerdate);
          if (matcherObj.matches())
            {
                return 1;
            }
            else
            {
                return 0;
            }
    }

its giving me compile time error at

String regEx =
            "^(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\d\d$";

saying invalid escape sequences.

Can any one figure out where I am wrong or any other way to validate date expression?

Answer 1

Java will treat \ inside a string as starting an escape sequence. Make sure you use \ instead (so that you get an actual \ character in the string) and you should be ok.

Quick Update: As Etienne points out, if you actually want a \ in the RegEx itself, you’ll need to use \\, since that will produce \ in the string, which will produce \ in the RegEx.

Your regex after correction:

String regEx ="^(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\\d{2}$";