Here you can find the source of toHexString(byte[] bytes)
public static String toHexString(byte[] bytes)
//package com.java2s; /**/* w w w. jav a 2 s. c o m*/ * Copyright (C) 2017 Lucifer Wong * * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except * in compliance with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software distributed under the License * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express * or implied. See the License for the specific language governing permissions and limitations under * the License. */ public class Main { public static String toHexString(byte[] bytes) { StringBuilder hexString = new StringBuilder(); for (int i = 0; i < bytes.length; i++) { hexString.append(enoughZero(Integer.toHexString(bytes[i] & 0xff), 2)); } return hexString.toString(); } public static String enoughZero(String str, int len) { while (str.length() < len) { str = "0" + str; } return str; } public static String toString(Object object, String nullStr) { return object == null ? nullStr : object.toString(); } }