Java – Convert String to int

In Java, you can use Integer.parseInt() to convert a String to int.

1. Integer.parseInt() Examples

Example to convert a String “10” to an primitive int.

    String number = "10";    int result = Integer.parseInt(number);              System.out.println(result);

Output

10

2. Integer.valueOf() Examples

Alternatively, you can use Integer.valueOf(), it will returns an Integer object.

    String number = "10";    Integer result = Integer.valueOf(number);           System.out.println(result);

Output

10

Note
In summary, parseInt(String) returns a primitive int, whereas valueOf(String) returns a new Integer() object.

3. NumberFormatException

If the string does not contain a parsable integer, a NumberFormatException will be thrown.

    String number = "10A";    int result = Integer.parseInt(number);    System.out.println(result);

Output

Exception in thread "main" java.lang.NumberFormatException: For input string: "10A"    at java.lang.NumberFormatException.forInputString(Unknown Source)    at java.lang.Integer.parseInt(Unknown Source)    at java.lang.Integer.valueOf(Unknown Source)