下面两个都是在生成sign签名时候用到的方式，有什么区别？

第一种：

import org.apache.commons.codec.digest.DigestUtils;String sign = DigestUtils.md5Hex(string);

 

第二种：

方法片段：import java.security.MessageDigest;try {            byte[] array = computeHash(params);            StringBuilder stringBuilder = new StringBuilder();            for (int i = 0; i < array.length; i++) {                byte b = array[i];                String text = Integer.toHexString(b & 0xFF);                if (text.length() == 1) {                    stringBuilder.append("0");                }                stringBuilder.append(text);            }            return stringBuilder.toString();        } catch (NoSuchAlgorithmException e) {            e.printStackTrace();        }============================public static byte[] computeHash(String input) throws NoSuchAlgorithmException {        MessageDigest digest = MessageDigest.getInstance("MD5");        digest.reset();        byte[] utf8bytes = null;        try {            utf8bytes = input.getBytes("UTF-8");            // digest.update(utf8bytes);        } catch (UnsupportedEncodingException e) {            e.printStackTrace();        }        return digest.digest(utf8bytes);    }

 

 

对比一下两种的区别