I want to append an attribute an existing element in XML using Java. For example:
<employee>
<details name="Jai" age="25"/>
<details name="kishore" age="30"/>
</employee>
It want to add weight to it (assume that it is calculated and then appended in response). How can I append that to all items?
<details name="Jai" age="25" weight="55"/>
import org.w3c.dom.*;
import java.io.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
public class AddAndPrint {
public static void main(String[] args) {
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
Document doc = docBuilder.parse("/path/to/file.xml");
NodeList employees = document.getElementsByTagName("employee");
for (Node employee : employees) {
for (Node child : employee.getChildNodes() {
if ("details".equals(child.getNodeName()) child.setAttribute("weight", "150");
}
}
try {
Source source = new DOMSource(doc);
StringWriter stringWriter = new StringWriter();
Result result = new StreamResult(stringWriter);
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer();
transformer.transform(source, result);
System.out.println(stringWriter.getBuffer().toString());
} catch (TransformerConfigurationException e) {
e.printStackTrace();
} catch (TransformerException e) {
e.printStackTrace();
}
}
}
Here is a quick solution based on jdom:
public static void main(String[] args) throws JDOMException, IOException {
File xmlFile = new File("employee.xml");
SAXBuilder builder = new SAXBuilder();
Document build = builder.build(xmlFile);
XPath details = XPath.newInstance("//details");
List<Element> detailsNodes = details.selectNodes(build);
for (Element detailsNode:detailsNodes) {
detailsNode.setAttribute("weight", "70"); // static weight for demonstration
}
XMLOutputter outputter = new XMLOutputter(Format.getPrettyFormat());
outputter.output(build, System.out);
}
First, we build a document (SAXBuilder), next we create a XPath expression for the details node, then we iterate through the elements for that expression and add the weight attribute.
The last two lines just verify that it's white magic :-)
