DOM tree traversal to get (name, value) attribute pairs and leaf nodes

Question

I want to go through an XML file in the DOM to get all the pairs (name, value):

• Names and values ​​of attributes;
• All leaf node names and their textual contents;

Therefore, the following XML file is given as an example:

<?xml version="1.0" encoding="UTF-8"?> <title text="title1"> <comment id="comment1"> <data> abcd </data> <data> efgh </data> </comment> <comment id="comment2"> <data> ijkl </data> <data> mnop </data> <data> qrst </data> </comment> </title> 

What I want as name value pairs:

 text=title1 id=comment1 data=abcd data=efgh id=commment2 data=ijkl data=mnop data=qrst 

Answer 1

A simpler solution would be to use XPath to retrieve all pairs of name values, as in the following example. You can also skip the DOM construct and invoke the evaluation directly on the InputSource . XPath expression

 //@* | //*[not(*)] 

corresponds to the union of all attributes and all nodes that do not have child nodes.

 import java.io.StringReader; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.xpath.XPath; import javax.xml.xpath.XPathConstants; import javax.xml.xpath.XPathFactory; import org.w3c.dom.Document; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.InputSource; public class Test { private static final String xml = "<title text='title1'>\n" + " <comment id='comment1'>\n" + " <data> abcd </data>\n" + " <data> efgh </data>\n" + " </comment>\n" + " <comment id='comment2'>\n" + " <data> ijkl </data>\n" + " <data> mnop </data>\n" + " <data> qrst </data>\n" + " </comment>\n" + "</title>\n"; public static void main(String[] args) throws Exception { DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder(); Document doc = builder.parse(new InputSource(new StringReader(xml))); XPathFactory xpf = XPathFactory.newInstance(); XPath xp = xpf.newXPath(); NodeList nodes = (NodeList)xp.evaluate("//@* | //*[not(*)]", doc, XPathConstants.NODESET); System.out.println(nodes.getLength()); for (int i=0, len=nodes.getLength(); i<len; i++) { Node item = nodes.item(i); System.out.println(item.getNodeName() + " : " + item.getTextContent()); } } } 

Answer 2

How about something like:

  String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" + "<title text=\"title1\">\n" + " <comment id=\"comment1\">\n" + " <data> abcd </data>\n" + " <data> efgh </data>\n" + " </comment>\n" + " <comment id=\"comment2\">\n" + " <data> ijkl </data>\n" + " <data> mnop </data>\n" + " <data> qrst </data>\n" + " </comment>\n" + "</title>\n"; try { DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder(); Document doc = builder.parse(new InputSource(new StringReader(xml))); DocumentTraversal traversal = (DocumentTraversal) doc; NodeIterator iterator = traversal.createNodeIterator( doc.getDocumentElement(), NodeFilter.SHOW_ELEMENT, null, true); for (Node n = iterator.nextNode(); n != null; n = iterator.nextNode()) { //System.out.println("Element: " + ((Element) n).getTagName()); String tagname = ((Element) n).getTagName(); if(tagname.equals("title")) { System.out.println("text=" + ((Element)n).getAttribute("text")); } else if(tagname.equals("comment")) { System.out.println("id=" + ((Element)n).getAttribute("id")); } else if(tagname.equals("data")) { System.out.println("data=" + ((Element)n).getTextContent()); } else { System.out.println("Unhandled element"); } } } catch (Exception e) { e.printStackTrace(); } 

Okay, so you were unhappy with this, how about this:

  String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" + "<title text=\"title1\">\n" + " <comment id=\"comment1\">\n" + " <data> abcd </data>\n" + " <data> efgh </data>\n" + " </comment>\n" + " <comment id=\"comment2\">\n" + " <data> ijkl </data>\n" + " <data> mnop </data>\n" + " <data> qrst </data>\n" + " </comment>\n" + "</title>\n"; try { DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder(); Document doc = builder.parse(new InputSource(new StringReader(xml))); DocumentTraversal traversal = (DocumentTraversal) doc; NodeIterator iterator = traversal.createNodeIterator( doc.getDocumentElement(), NodeFilter.SHOW_ELEMENT, null, true); for (Node n = iterator.nextNode(); n != null; n = iterator.nextNode()) { //System.out.println("Element: " + ((Element) n).getTagName()); String tagname = ((Element) n).getTagName(); NamedNodeMap map = ((Element)n).getAttributes(); if(map.getLength() > 0) { for(int i=0; i<map.getLength(); i++) { Node node = map.item(i); System.out.println(node.getNodeName() + "=" + node.getNodeValue()); } } else { System.out.println(tagname + "=" + ((Element)n).getTextContent()); } } } catch (Exception e) { e.printStackTrace(); }