Java tutorial
//package com.java2s; /******************************************************************************* * Copyright (c) 2010-2012 by Min Cai (min.cai.china@gmail.com). * * This file is part of the PickaPack library. * * PickaPack is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * PickaPack is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with PickaPack. If not, see <http://www.gnu.org/licenses/>. ******************************************************************************/ import org.w3c.dom.Node; import javax.xml.namespace.QName; import javax.xml.xpath.XPath; import javax.xml.xpath.XPathConstants; import javax.xml.xpath.XPathExpressionException; import javax.xml.xpath.XPathFactory; public class Main { private static XPath xpath = XPathFactory.newInstance().newXPath(); /** * Get the first node from the specified object using the specified XPath expression. * * @param obj the object * @param xpathExpression the XPath expression * @return the first node from the specified object matched using the specified XPath expression */ public static Node getFirstByXPath(Object obj, String xpathExpression) { return evaluate(obj, xpathExpression, XPathConstants.NODE); } @SuppressWarnings("unchecked") private static <T> T evaluate(Object obj, String xpathExpression, QName qName) { try { return (T) xpath.compile(xpathExpression).evaluate(obj, qName); } catch (XPathExpressionException e) { throw new RuntimeException(e); } } }