Question

I’m new to Java. I created this code in order to check input field for string or number.

try {
    int x = Integer.parseInt(value.toString());
} catch (NumberFormatException nFE) {
    // If this is a string send error message
    throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR,
            "  " + findValue + " must be number!", null));
}

How I can create the same check for number but using just if(){} without try-catch?

Answer 1

You can use a pattern with String#matches method: –

String str = "6";

if (str.matches("[-]?\\d+")) {
    int x = Integer.parseInt(str);
}

"[-]?\\d+" pattern will match any sequence of digits, preceded by an optional - sign.

"\\d+" means match one or more digits.