md5算法的简单小例子

 

/** * md5加密算法 * @param str * @return * @author QQ:894204994 */private static String md5(String str) {if (str == null) {throw new BusinessRuntimeException("message","处理数据错误，请联系管理人员");}MessageDigest messageDigest = null;try {messageDigest = MessageDigest.getInstance("MD5");messageDigest.reset();messageDigest.update(str.getBytes("utf-8"))} catch (NoSuchAlgorithmException e) { throw new BusinessRuntimeException("message","处理数据错误，请联系管理人员");} catch (UnsupportedEncodingException e) {throw new BusinessRuntimeException("message","处理数据错误，请联系管理人员");}byte[] byteArray = messageDigest.digest();StringBuffer md5StrBuff = new StringBuffer();               //byte转化成intfor (int i = 0; i < byteArray.length; i++) {String hex = Integer.toHexString(0xFF & byteArray[i]);if (hex.length() == 1) {md5StrBuff.append('0');}md5StrBuff.append(hex);}return md5StrBuff.toString();}