关于使用Dom创建xml文档时<?xml version="1.0" endocing="utf-8"?>的问题

Question

TransformerFactory tFactory = TransformerFactory.newInstance();
            Transformer transformer = tFactory.newTransformer();
            Properties properties = transformer.getOutputProperties();
            properties.setProperty(OutputKeys.ENCODING, "gb2312");////  就是这句了
            properties.setProperty(OutputKeys.METHOD, "xml");
            properties.setProperty(OutputKeys.VERSION, "1.0");
            properties.setProperty(OutputKeys.INDENT, "no");
            transformer.setOutputProperties(properties);            DOMSource source = new DOMSource(doc);其中最后一句中得doc是拼好得XML。比如：
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();
            Document doc = db.newDocument();
            Element root = doc.createElement("DSTreeRoot");
            ..........................（就不细写了）