String to Int in java - Likely bad data, need to avoid exceptions

Question

Seeing as Java doesn\'t have nullable types, nor does it have a TryParse(), how do you handle input validation without throwing an exceptions?

The usual way:

Answer 1

Here's how I do it:

public Integer parseInt(String data) {
  Integer val = null;
  try {
    val = Integer.parseInt(userdata);
  } catch (NumberFormatException nfe) { }
  return val;
}

Then the null signals invalid data. If you want a default value, you could change it to:

public Integer parseInt(String data,int default) {
  Integer val = default;
  try {
    val = Integer.parseInt(userdata);
  } catch (NumberFormatException nfe) { }
  return val;
}