Using child axis in XPath expression
In this section you will know about the use of
"child axis". "child axis" consists of the children of
context node. It can be omitted as well because it is the default axis you may
or may not use it.
In this example we have created an XML file "persons.xml"
as in our previous section, which is necessary to execute XPath query on
to it. This "persons.xml" contains information related to name,
age, gender of different persons.
Here is the full source code for persons.xml file
as follows :
persons.xml
<?xml version="1.0" ?>
<information>
<person id="1">
<name>Deep</name>
<age>34</age>
<gender>Male</gender>
</person>
<person id="2">
<name>Kumar</name>
<age>24</age>
<gender>Male</gender>
</person>
<person id="3">
<name>Deepali</name>
<age>19</age>
<gender>Female</gender>
</person>
<!-- more persons... -->
</information> |
Now we have declared a class XPathChildAxis and
in this class we are parsing the XML file with JAXP. First of all we need
to load the document into DOM Document object. We have put that
persons.xml file in that current working directory.
DocumentBuilderFactory domFactory =
DocumentBuilderFactory.newInstance();
domFactory.setNamespaceAware(true);
DocumentBuilder builder = domFactory.newDocumentBuilder();
Document doc = builder.parse("persons.xml"); |
Above lines of code parses "persons.xml"
file and creates a Document object. Next we have created XPath object
with the use of XPathFactory.
XPath xpath = XPathFactory.newInstance().newXPath(); |
"//child::person/name" is as same as
"//person/name".
Here is the example code for XPathChildAxis.java
as follows:
XPathChildAxis.java
import org.w3c.dom.*;
import javax.xml.xpath.*;
import javax.xml.parsers.*;
import java.io.IOException;
import org.xml.sax.SAXException;
public class XPathChildAxis {
public static void main(String[] args)
throws ParserConfigurationException, SAXException,
IOException, XPathExpressionException {
DocumentBuilderFactory domFactory =
DocumentBuilderFactory.newInstance();
domFactory.setNamespaceAware(true);
DocumentBuilder builder = domFactory.newDocumentBuilder();
Document doc = builder.parse("persons.xml");
XPath xpath = XPathFactory.newInstance().newXPath();
XPathExpression expr =
xpath.compile("//child::person/name/text()");
// using Child Axis
Object result =
expr.evaluate(doc, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
System.out.println(nodes.item(i).getNodeValue());
}
}
}
|
Output:
Download Source Code
|
Del.icio.us
Digg
Google
Spurl
Blink
Furl
Simpy
Y! MyWeb
