How to Convert a String to an Integer in Java and Set to Zero if Null?

How can I convert a string to an integer in Java, ensuring that the integer is set to zero if the string is null?

String inputString = null;

In Java, converting a string to an integer can be straightforward, but special care must be taken when dealing with null values. The goal is to ensure that if the input string is null, the return value should be zero instead of throwing a NullPointerException or NumberFormatException.

public class StringToIntConverter {
    public static int convertStringToInt(String input) {
        if (input == null) {
            return 0; // Return 0 if the input string is null
        }
        try {
            return Integer.parseInt(input.trim()); // Convert the string to int
        } catch (NumberFormatException e) {
            return 0; // Return 0 for any number format issue
        }
    }
}

Causes

• Null input strings leading to errors during conversion.
• Incorrect assumptions about the string's content (e.g., empty strings or non-numeric characters).

Solutions

• Use a null check before conversion to safely handle the null case.
• Utilize the `Integer.parseInt()` method with proper exception handling.

Mistake: Assuming the string is always valid and not checking for null.

Solution: Always check for null before conversion.

Mistake: Not trimming the string, leading to exceptions on strings with whitespace.

Solution: Use `input.trim()` to clean up the string before parsing.