java - 格式化 XML 文件 : Indentation

Question

我正在尝试编写具有适当缩进的 XML 文件。这是我的代码:

   public class WebVideo {

 private final String C_XMLFILEPATH = "resources/video.xml";
 private String itemId;
 private String videoPath;

 public WebVideo(long itemId, String videoPath) {
  this.itemId = Long.toString(itemId);
  this.videoPath = videoPath;
 }

 public void saveVideo() throws ParserConfigurationException, IOException,
   TransformerFactoryConfigurationError, TransformerException,
   SAXException {
  File xmlFile = new File(C_XMLFILEPATH);
  DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory
    .newInstance();
  DocumentBuilder documentBuilder = documentBuilderFactory
    .newDocumentBuilder();
  Document document = null;
  Element rootElement = null;

  if (xmlFile.exists()) {
   document = documentBuilder.parse(xmlFile);
   rootElement = document.getDocumentElement();

  } else {
   document = documentBuilder.newDocument();
   rootElement = document.createElement("Videos");
   document.appendChild(rootElement);
  }

  Element itemElement = document.createElement("Video");
  rootElement.appendChild(itemElement);

  Element idElement = document.createElement("Id");
  Text id = document.createTextNode(itemId);
  idElement.appendChild(id);
  itemElement.appendChild(idElement);

  Element pathElement = document.createElement("Path");
  Text path = document.createTextNode(videoPath);
  pathElement.appendChild(path);
  itemElement.appendChild(pathElement);

  Transformer transformer = TransformerFactory.newInstance()
    .newTransformer();
  transformer.setOutputProperty(OutputKeys.INDENT, "yes");
  transformer.setOutputProperty(
    "{http://xml.apache.org/xslt}indent-amount", "4");

  StreamResult streamResult = new StreamResult(new StringWriter());
  DOMSource domSource = new DOMSource(document);
  transformer.transform(domSource, streamResult);
  String xmlString = streamResult.getWriter().toString();

  BufferedWriter bufferedWriter = new BufferedWriter(
    new OutputStreamWriter(new FileOutputStream(xmlFile)));
  bufferedWriter.write(xmlString);
  bufferedWriter.flush();
  bufferedWriter.close();
 }
}

一切正常，但如果您仔细查看输出 XML 文件，就会发现在我追加新元素时出现问题。输出 XML 文件在这里:

  <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    <Videos>
        <Video>
            <Id>1</Id>
            <Path>path</Path>
        </Video>
    <Video>
            <Id>2</Id>
            <Path>path</Path>
        </Video>
    </Videos>

标签与标签在同一个缩进中。我怎么解决这个问题？谢谢。

Answer 1

查看此答案以了解 XML 的 pretty-print :How to pretty print XML from Java?