code: private byte[] doDigest(byte[]... datas) {
  		for (byte[] data : datas) {
  			if (null != data) {
  				this.digest.update(data);
  			}
  		}
  		return this.digest.digest();
  	}
docs: 生成摘要
  
  @param datas 数据bytes
  @return 摘要bytes
  @since 4.4.3