Java - convert hex to int

Short solution:

String hex = "a";
int number = Integer.parseInt(hex, 16);

System.out.println(number); // 10

The best way to convert hex String to int in java is to use Integer.parseInt() method.

Syntax:

Integer.parseInt(String hexString, int radix)

1. Convert couple of different hex to int

public class Example1 {

    public static void main(String[] args) {

        System.out.println( Integer.parseInt("5", 16) );  // 5
        System.out.println( Integer.parseInt("a", 16) );  // 10
        System.out.println( Integer.parseInt("b", 16) );  // 11
        System.out.println( Integer.parseInt("f", 16) );  // 15
        System.out.println( Integer.parseInt("10", 16) ); // 16
        System.out.println( Integer.parseInt("1f", 16) ); // 31
        System.out.println( Integer.parseInt("20", 16) ); // 32
        System.out.println( Integer.parseInt("21", 16) ); // 33
    }
}

Output:

5
10
11
15
16
31
32
33

2. Convert hex to int in loop - from 0 to 20

public class Example2 {

    public static void main(String[] args) {

        System.out.println("Hex | Dec");

        for (int number = 0; number <= 16; number++) {

            String hex = Integer.toHexString(number);
            int backToDecimal = Integer.parseInt(hex, 16);

            System.out.println(String.format("%3s", hex) + " - "
                    + String.format("%3s", backToDecimal));
        }
    }
}

Output:

Hex | Dec
  0 -   0
  1 -   1
  2 -   2
  3 -   3
  4 -   4
  5 -   5
  6 -   6
  7 -   7
  8 -   8
  9 -   9
  a -  10
  b -  11
  c -  12
  d -  13
  e -  14
  f -  15
 10 -  16