Question

I want to create a method to validate a date by using SimpleDateFormat.

If the date is valid(e.g. 02/09/2012 or 2/09/2012 or 02/9/2012), this method should return true.

But if the format of the date is wrong(e.g. 02/09/201X) or logically wrong(e.g. 32/09/2012), this method should return false.

I try to write this method like this:

private boolean isValidDate(String date) {
        DateFormat df1 = new SimpleDateFormat("dd-MM-yyyy");
        DateFormat df2 = new SimpleDateFormat("d-MM-yyyy");
        DateFormat df3 = new SimpleDateFormat("dd-M-yyyy");
        Date d = null;
        String s = null;

        try {
            d = df1.parse(date);
        }catch (Exception e1) {
            try{
                d = df2.parse(date);
            }catch (Exception e2) {
                try {
                    d= df3.parse(date);
                }catch (Exception e3) {
                    return false;
                }
                s = df3.format(d);
                return date.equals(s);
            }
            s = df2.format(d);
            return date.equals(s);
        }
        s = df1.format(d);
        return date.equals(s);
    }

But if I validate a date, for instance, 2/09/2012, it returns false (actually it should return true). I have no idea why… Can anyone find what’s the problem with my code, or this logic is totally wrong? Is there any better way to do this validation?

Answer 1

Your input is in the format 2/09/2012 not 2-09-2012, so your dateformat should be like below:

    DateFormat df1 = new SimpleDateFormat("dd/MM/yyyy");
    DateFormat df2 = new SimpleDateFormat("d/MM/yyyy");
    DateFormat df3 = new SimpleDateFormat("dd/M/yyyy");