Java - Write code to convert string to MD5 hash and format the result

Requirements

Write code to convert string to MD5 hash and format the result

Demo

//package com.book2s;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Main {
    public static void main(String[] argv) {
        String str = "book2s.com";
        System.out.println(str2md5(str));
    }//from  w  ww. ja  v  a2 s. c o m

    private static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4',
            '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

    public static String str2md5(String str) {
        try {
            MessageDigest algorithm = MessageDigest.getInstance("MD5");
            algorithm.reset();
            algorithm.update(str.getBytes());
            byte[] bytes = algorithm.digest();
            StringBuilder hexString = new StringBuilder();
            for (byte b : bytes) {
                hexString.append(HEX_DIGITS[b >> 4 & 0xf]);
                hexString.append(HEX_DIGITS[b & 0xf]);
            }
            return hexString.toString();
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }
}