Java Language XML Parsing using the JAXP APIs Parsing and navigating a document using the DOM API
Example
Considering the following document :
<?xml version='1.0' encoding='UTF-8' ?>
<library>
<book id='1'>Effective Java</book>
<book id='2'>Java Concurrency In Practice</book>
</library>
One can use the following code to build a DOM tree out of a String :
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.StringReader;
public class DOMDemo {
public static void main(String[] args) throws Exception {
String xmlDocument = "<?xml version='1.0' encoding='UTF-8' ?>"
+ "<library>"
+ "<book id='1'>Effective Java</book>"
+ "<book id='2'>Java Concurrency In Practice</book>"
+ "</library>";
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
// This is useless here, because the XML does not have namespaces, but this option is usefull to know in cas
documentBuilderFactory.setNamespaceAware(true);
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
// There are various options here, to read from an InputStream, from a file, ...
Document document = documentBuilder.parse(new InputSource(new StringReader(xmlDocument)));
// Root of the document
System.out.println("Root of the XML Document: " + document.getDocumentElement().getLocalName());
// Iterate the contents
NodeList firstLevelChildren = document.getDocumentElement().getChildNodes();
for (int i = 0; i < firstLevelChildren.getLength(); i++) {
Node item = firstLevelChildren.item(i);
System.out.println("First level child found, XML tag name is: " + item.getLocalName());
System.out.println("\tid attribute of this tag is : " + item.getAttributes().getNamedItem("id").getTextContent());
}
// Another way would have been
NodeList allBooks = document.getDocumentElement().getElementsByTagName("book");
}
}
The code yields the following :
Root of the XML Document: library
First level child found, XML tag name is: book
id attribute of this tag is : 1
First level child found, XML tag name is: book
id attribute of this tag is : 2
