How to convert a hexadecimal number to a decimal number in Java

How to convert a hexadecimal number to a decimal number in Java

package com.swift;import java.util.Scanner;public class Hex2Decimal {    public static void main(String[] args) {        Scanner scan = new Scanner(System.in);        System.out.println("please enter a Hex:");        String hex = scan.nextLine();        hex = hex.toUpperCase();        System.out.println("The hex is:" + hex);        int decimal = 0;        for (int i = 0; i < hex.length(); i++) {            if (hexChar2Decimal(hex.charAt(hex.length() - 1 - i)) != -1) {                decimal = (int) (decimal + hexChar2Decimal(hex.charAt(hex.length() - 1 - i)) * Math.pow(16, i));            } else {                System.out.println("enter error, decimal will be zero!");                break;            }        }        System.out.println("decimal=" + decimal);    }    private static int hexChar2Decimal(char charAt) {        if (charAt >= 'A' && charAt <= 'F')            return charAt - 'A' + 10;        else if (charAt >= '0' && charAt <= '9')            return charAt-'0';        else            return -1;    }}

Hexadecimal AF3 conversion principle: 3*16 ^ 0 + F * 16 ^ 1 + A * 16 ^ 2 where ^ represents A power operation, F and A must be converted to decimal numbers 15 and 10.