code: public static void save(final List<CodedMessage> messageList, final OutputStream writer)
  		throws CodedMessageException {
  		try {
  			Document document = save0(messageList);
  			Transformer transformer = TRANSFORMER_FACTORY.newTransformer();
  			transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
  			transformer.transform(new DOMSource(document), new StreamResult(writer));
  		} catch (TransformerException e) {
  			throw new CodedMessageException(e, "CodedMessage.SaveXMLError");
  		}
  	}
docs: 保存到文件。
  
  @param messageList
  消息记录组
  @param writer
  输出流
  @throws CodedMessageException
  操作异常