关于XmlUtils类(1)

package com.xiao.demo.utils;


import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.StringReader;
import javax.xml.namespace.NamespaceContext;
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.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
/**
* xml常用工具类
*/
public class XmlUtils {
private static final Logger LOGGER = LoggerFactory.getLogger(XmlUtils.class);


public static NodeList runXpath(Node doc, String xquery, NamespaceContext ns) {
NodeList list = null;
try {
XPathFactory factory = XPathFactory.newInstance();
XPath xpath = factory.newXPath();
if (null != ns) {
xpath.setNamespaceContext(ns);
}
XPathExpression expression = xpath.compile(xquery);


Object result = expression.evaluate(doc, XPathConstants.NODESET);
list = (NodeList) result;
} catch (Exception e) {
LOGGER.warn("XMLUtils: unable to evaluate xpath", e);
LOGGER.error("", e);
}
return list;
}


public static String getValueByXpath(Node doc, String xquery) {
try {
XPathFactory factory = XPathFactory.newInstance();
XPath xpath = factory.newXPath();
XPathExpression expression = xpath.compile(xquery);
String result = (String) expression.evaluate(doc, XPathConstants.STRING);
return result;
} catch (Exception e) {
LOGGER.error("", e);
LOGGER.warn("XMLUtils: unable to evaluate xpath", e);
}
return null;
}


public static String nodeAsString(Node node) {
String nodeStr = "";
TransformerFactory tff = TransformerFactory.newInstance();
try {
Transformer tf = tff.newTransformer();
tf.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
ByteArrayOutputStream bos = new ByteArrayOutputStream();
tf.transform(new DOMSource(node), new StreamResult(bos));
return bos.toString("UTF-8");
} catch (Exception e) {
LOGGER.warn("XMLUtils#nodeAsString: ", e);
LOGGER.error("", e);
}


return nodeStr;
}


public static Document getW3CDom(String xmlStr) throws ParserConfigurationException,
SAXException, IOException {
StringReader sr = new StringReader(xmlStr);
InputSource is = new InputSource(sr);
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(is);


return doc;
}

}