File d = new File(dir);
XPathFactory factory = XPathFactory.newInstance();
XPath xPath = factory.newXPath();
InputSource inputSource = new InputSource(new FileInputStream(d));
String expression = "/employees/employee[loginID/text()=‘" + username + "‘ and passwd/text()=‘" + password
        + "‘]";
nodes = (NodeList) xPath.evaluate(expression, inputSource, XPathConstants.NODESET);