Question

I have a ResultSet that i iterate over and i create a report like view (html).
The problem is that some columns return Long values (as a result of mathematical function in SQL).

Is there an easy way that I can identify this values by DataType?

Lets say i want to do something like this

String x = rs.getString(1);
if(MyUtilClass.isOfTypeLong(x)){
  //implement my bussiness logig
}

I have seen this post How do you determine the type of data contained in a string? . If there isn’t anything better right now, I will proceed with the regEx solution.

Answer 1

Why don’t you try Long.valueOf(String) to first parse it as a Long, and failing that parse it as a Double with Double.valueOf(String)?

Both throw a NumberFormatException if the string cannot be parsed.

public static void main(String[] args) throws Exception {
    final String s1 = "1234567890";
    System.out.println(isParsableAsLong(s1));    // true
    System.out.println(isParsableAsDouble(s1));  // true

    final String s2 = "1234.56789";
    System.out.println(isParsableAsLong(s2));   // false
    System.out.println(isParsableAsDouble(s2)); // true
}

private static boolean isParsableAsLong(final String s) {
    try {
        Long.valueOf(s);
        return true;
    } catch (NumberFormatException numberFormatException) {
        return false;
    }
}

private static boolean isParsableAsDouble(final String s) {
    try {
        Double.valueOf(s);
        return true;
    } catch (NumberFormatException numberFormatException) {
        return false;
    }
}