dom實現xml格式化輸出（換行）

/**
   * 根據DOM生成XML文件
   */
  public void buildXmlFile() {
    TransformerFactory tfactory = TransformerFactory.newInstance();
    try {
      Transformer transformer = tfactory.newTransformer();
      DOMSource source = new DOMSource(doc);
      File file = new File("c:\\test.xml");
      if (file.exists()) {
        file.delete();
      }
      StreamResult result = new StreamResult(file);
      transformer.setOutputProperty("encoding", encoding);
      transformer.setOutputProperty(OutputKeys.INDENT,"yes");
      transformer.transform(source, result);
    }
    catch (Exception e) {
      e.printStackTrace();
    }
  }