import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

public class UseXPath{
    public static void main(String args[]){
        XPath xpath = XPathFactory.newInstance().newXPath();
        InputSource inputSource = new InputSource("test.xml");
        String expression = "//test/unko[@id='hello']";

        try {
            NodeList nodes = (NodeList) xpath.evaluate(expression, inputSource, XPathConstants.NODESET);
            for (int i = 0; i < nodes.getLength(); i++) {
                Node node = nodes.item(i);
                String str = node.getTextContent();
                System.out.println(str);
            }
        } catch (XPathExpressionException e) {
            e.printStackTrace();
        }
    }
}