日常工作中，对接一些硬件使用tcp通信，需要将输入输出流转16进制字符串再在表中找到与其对应的ASCII码，并转换作为结果。因此，这里整理了一个工具类，用于这三者的相互转换。

十六进制字符串转byte数组：

//十六进制字符串转byte数组public static byte[] hexStringToByteArray(String s) {int len = s.length();byte[] ba = new byte[len / 2];for(int i = 0; i < ba.length; ++i) {int j = i * 2;int t = Integer.parseInt(s.substring(j, j + 2), 16);byte b = (byte)(t & 255);ba[i] = b;}return ba;}

byte数组转十六进制字符串以小写字母形式显示：

//byte数组转十六进制字符串以小写字母形式显示public static String ByteArrayToHexString(byte[] bytes){StringBuilder sb = new StringBuilder();for (int i = 0; i < bytes.length; i++) {String hex = Integer.toHexString(0xFF & bytes[i]);if (hex.length() == 1) {sb.append('0');}sb.append(hex);}return sb.toString();}

ASCII码转十六进制字符串：

//ASCII码转十六进制字符串public static String ASCToHex(String str){char[] chars = str.toCharArray();StringBuffer hex = new StringBuffer();for(int i = 0; i < chars.length; i++){hex.append(Integer.toHexString((int)chars[i]));}return hex.toString();}

16进制字符串转ASCII码：

//16进制字符串转ASCII码public static String convertHexToASC(String hex){StringBuilder sb = new StringBuilder();StringBuilder temp = new StringBuilder();for( int i=0; i<hex.length()-1; i+=2 ){String output = hex.substring(i, (i + 2));int decimal = Integer.parseInt(output, 16);sb.append((char)decimal);temp.append(decimal);}return sb.toString();}

工具类HexToASCToBytes 完整代码：

package com.example.demo.utils;/*** @author zhangqianwei* @date /10/21 20:47*/public class HexToASCToBytes {//十六进制字符串与byte数组相互转换，常用于socket通信public static void main(String[] args) {String s = "2B";byte[] bytes = hexStringToByteArray(s);System.out.println("十六进制字符串转byte数组："+bytes);String hex = ByteArrayToHexString(bytes);System.out.println("byte数组转十六进制字符串："+hex);String ASC = convertHexToASC(s);System.out.println("十六进制字符串转ASCII码："+ASC);String hex2 = ASCToHex(ASC);System.out.println("ASCII码转十六进制字符串："+hex2);}//十六进制字符串转byte数组public static byte[] hexStringToByteArray(String s) {int len = s.length();byte[] ba = new byte[len / 2];for(int i = 0; i < ba.length; ++i) {int j = i * 2;int t = Integer.parseInt(s.substring(j, j + 2), 16);byte b = (byte)(t & 255);ba[i] = b;}return ba;}//byte数组转十六进制字符串以小写字母形式显示public static String ByteArrayToHexString(byte[] bytes){StringBuilder sb = new StringBuilder();for (int i = 0; i < bytes.length; i++) {String hex = Integer.toHexString(0xFF & bytes[i]);if (hex.length() == 1) {sb.append('0');}sb.append(hex);}return sb.toString();}//ASCII码转十六进制字符串public static String ASCToHex(String str){char[] chars = str.toCharArray();StringBuffer hex = new StringBuffer();for(int i = 0; i < chars.length; i++){hex.append(Integer.toHexString((int)chars[i]));}return hex.toString();}//16进制字符串转ASCII码public static String convertHexToASC(String hex){StringBuilder sb = new StringBuilder();StringBuilder temp = new StringBuilder();for( int i=0; i<hex.length()-1; i+=2 ){String output = hex.substring(i, (i + 2));int decimal = Integer.parseInt(output, 16);sb.append((char)decimal);temp.append(decimal);}return sb.toString();}}