code: private static byte[] sha1(byte[] data) {
  		MessageDigest md = null;
  		try {
  			md = MessageDigest.getInstance(ALGORITHM_SHA1);
  			md.reset();
  			md.update(data);
  			return md.digest();
  		} catch (Exception e) {
  			LogUtil.writeErrorLog("SHA1计算失败", e);
  			return null;
  		}
  	}
docs: sha1计算.
  
  @param datas
  待计算的数据
  @return 计算结果