Java Convert String to int

Java Convert String to int

Introduction: 

In Java, converting a String to an int is a common operation when dealing with user input, configuration files, or other data sources. The process involves parsing the numerical value from the String and converting it into an integer data type.

Method 1: 

Integer.parseInt()
The Integer.parseInt() method is a standard and widely-used way to convert a String to an int. It takes a String argument and returns an int value representing the parsed integer.

Code Example:

java
public class StringToIntExample {
    public static void main(String[] args) {
        String numberStr = "42";
        int convertedInt = Integer.parseInt(numberStr);

        System.out.println("Converted Integer: " + convertedInt);
    }
}

Explanation:

• In the code example above, we have a String variable numberStr initialized with the value "42".
• We use the Integer.parseInt() method to convert this String to an int. The method parses the numerical value from the String and converts it into the int data type.
• The resulting int value is stored in the variable convertedInt.
• Finally, we print the converted int value to the console using System.out.println().

Method 2: 

Integer.valueOf()
Another approach to convert a String to an int is by using the Integer.valueOf() method. This method returns an Integer object, which can be automatically unboxed to an int.

Code Example:

java
public class StringToIntExample {
    public static void main(String[] args) {
        String numberStr = "73";
        int convertedInt = Integer.valueOf(numberStr);

        System.out.println("Converted Integer: " + convertedInt);
    }
}

Explanation:

• In this code example, we have a String variable numberStr initialized with the value "73".
• We use the Integer.valueOf() method to convert this String to an Integer object.
• The Integer object is automatically unboxed to an int, and the resulting value is stored in the variable convertedInt.
• Finally, we print the converted int value to the console using System.out.println().

Important Note:
Both Integer.parseInt() and Integer.valueOf() methods will throw a NumberFormatException if the input String is not a valid integer. To handle this exception, it's recommended to use a try-catch block or check for validity using appropriate validation mechanisms before performing the conversion.

Remember, always validate user input or external data to avoid unexpected errors in your Java applications.