How do I convert a String to an int in Java?

25 Asked by nathan_4860 in Java , Asked on Mar 18, 2025

How to Convert a String to an int in Java

In Java, you can convert a String to an int using different methods, depending on the use case.

1. Using Integer.parseInt() (Most Common Method)

String str = "123";

int number = Integer.parseInt(str);

System.out.println(number); // Output: 123

This is the most efficient way.
Throws NumberFormatException if the string is not a valid number.

2. Using Integer.valueOf() (Returns an Integer Object)

String str = "456";

Integer number = Integer.valueOf(str);

System.out.println(number); // Output: 456

Returns an Integer object instead of a primitive int.
Useful when working with Integer objects instead of primitives.

3. Handling Errors with Try-Catch

String str = "abc";  

try {

    int number = Integer.parseInt(str);

    System.out.println(number);

} catch (NumberFormatException e) {

    System.out.println("Invalid number format!");

}

Helps prevent crashes if the input is not a valid number.

Which Method to Use?

Use Integer.parseInt() for simple cases when you need an int.
Use Integer.valueOf() when working with Integer objects.
Always handle exceptions if input data is uncertain.

How do I convert a String to an int in Java?

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