Java tutorial
import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.StringReader; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.transform.OutputKeys; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerException; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import org.w3c.dom.Document; import org.w3c.dom.NamedNodeMap; import org.w3c.dom.Node; import org.xml.sax.EntityResolver; import org.xml.sax.InputSource; import org.xml.sax.SAXException; /** * Few simple utils to read DOM * * @author Costin Manolache */ public class DomUtil { // -------------------- DOM utils -------------------- /** * Get the trimed text content of a node or null if there is no text */ public static String getContent(Node n) { if (n == null) return null; Node n1 = DomUtil.getChild(n, Node.TEXT_NODE); if (n1 == null) return null; String s1 = n1.getNodeValue(); return s1.trim(); } /** * Get the first element child. * * @param parent * lookup direct childs * @param name * name of the element. If null return the first element. */ public static Node getChild(Node parent, String name) { if (parent == null) return null; Node first = parent.getFirstChild(); if (first == null) return null; for (Node node = first; node != null; node = node.getNextSibling()) { // System.out.println("getNode: " + name + " " + node.getNodeName()); if (node.getNodeType() != Node.ELEMENT_NODE) continue; if (name != null && name.equals(node.getNodeName())) { return node; } if (name == null) { return node; } } return null; } public static String getAttribute(Node element, String attName) { NamedNodeMap attrs = element.getAttributes(); if (attrs == null) return null; Node attN = attrs.getNamedItem(attName); if (attN == null) return null; return attN.getNodeValue(); } public static void setAttribute(Node node, String attName, String val) { NamedNodeMap attributes = node.getAttributes(); Node attNode = node.getOwnerDocument().createAttribute(attName); attNode.setNodeValue(val); attributes.setNamedItem(attNode); } public static void removeAttribute(Node node, String attName) { NamedNodeMap attributes = node.getAttributes(); attributes.removeNamedItem(attName); } /** * Set or replace the text value */ public static void setText(Node node, String val) { Node chld = DomUtil.getChild(node, Node.TEXT_NODE); if (chld == null) { Node textN = node.getOwnerDocument().createTextNode(val); node.appendChild(textN); return; } // change the value chld.setNodeValue(val); } /** * Find the first direct child with a given attribute. * * @param parent * @param elemName * name of the element, or null for any * @param attName * attribute we're looking for * @param attVal * attribute value or null if we just want any */ public static Node findChildWithAtt(Node parent, String elemName, String attName, String attVal) { Node child = DomUtil.getChild(parent, Node.ELEMENT_NODE); if (attVal == null) { while (child != null && (elemName == null || elemName.equals(child.getNodeName())) && DomUtil.getAttribute(child, attName) != null) { child = getNext(child, elemName, Node.ELEMENT_NODE); } } else { while (child != null && (elemName == null || elemName.equals(child.getNodeName())) && !attVal.equals(DomUtil.getAttribute(child, attName))) { child = getNext(child, elemName, Node.ELEMENT_NODE); } } return child; } /** * Get the first child's content ( ie it's included TEXT node ). */ public static String getChildContent(Node parent, String name) { Node first = parent.getFirstChild(); if (first == null) return null; for (Node node = first; node != null; node = node.getNextSibling()) { // System.out.println("getNode: " + name + " " + node.getNodeName()); if (name.equals(node.getNodeName())) { return getContent(node); } } return null; } /** * Get the first direct child with a given type */ public static Node getChild(Node parent, int type) { Node n = parent.getFirstChild(); while (n != null && type != n.getNodeType()) { n = n.getNextSibling(); } if (n == null) return null; return n; } /** * Get the next sibling with the same name and type */ public static Node getNext(Node current) { String name = current.getNodeName(); int type = current.getNodeType(); return getNext(current, name, type); } /** * Return the next sibling with a given name and type */ public static Node getNext(Node current, String name, int type) { Node first = current.getNextSibling(); if (first == null) return null; for (Node node = first; node != null; node = node.getNextSibling()) { if (type >= 0 && node.getNodeType() != type) continue; // System.out.println("getNode: " + name + " " + node.getNodeName()); if (name == null) return node; if (name.equals(node.getNodeName())) { return node; } } return null; } public static class NullResolver implements EntityResolver { public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException { return new InputSource(new StringReader("")); } } /** * Read XML as DOM. */ public static Document readXml(InputStream is) throws SAXException, IOException, ParserConfigurationException { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); dbf.setValidating(false); dbf.setIgnoringComments(false); dbf.setIgnoringElementContentWhitespace(true); // dbf.setCoalescing(true); // dbf.setExpandEntityReferences(true); DocumentBuilder db = null; db = dbf.newDocumentBuilder(); db.setEntityResolver(new NullResolver()); // db.setErrorHandler( new MyErrorHandler()); Document doc = db.parse(is); return doc; } public static void writeXml(Node n, OutputStream os) throws TransformerException { TransformerFactory tf = TransformerFactory.newInstance(); // identity Transformer t = tf.newTransformer(); t.setOutputProperty(OutputKeys.INDENT, "yes"); t.transform(new DOMSource(n), new StreamResult(os)); } }