How to Create an XML Document with Namespaces in Java

Question

How can I create an XML document using namespaces in Java?

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class CreateXMLWithNamespaces {
    public static void main(String[] args) throws Exception {
        // Create a DocumentBuilderFactory
        DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder docBuilder = docFactory.newDocumentBuilder();

        // Create a new document
        Document doc = docBuilder.newDocument();

        // Create the root element with a namespace
        Element rootElement = doc.createElementNS("http://example.com/ns", "ns:root");
        doc.appendChild(rootElement);

        // Create child element with a namespace
        Element childElement = doc.createElementNS("http://example.com/ns", "ns:child");
        childElement.appendChild(doc.createTextNode("This is a child element"));
        rootElement.appendChild(childElement);

        // Write the content into an XML file
        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        DOMSource source = new DOMSource(doc);
        StreamResult result = new StreamResult(System.out);

        transformer.transform(source, result);
    }
}

Answer

Creating an XML document with namespaces in Java involves using the DOM (Document Object Model) API provided by the Java Standard Library. Namespaces are crucial when you need to avoid element name conflicts, especially in XML documents that may integrate different XML schemas.

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class CreateXMLWithNamespaces {
    public static void main(String[] args) throws Exception {
        // ... (Complete code as shown above)
    }
}

Causes

Namespaces are needed to avoid naming conflicts in XML documents.
To maintain XML validity and structure when integrating multiple XML sources.

Solutions

Use the DocumentBuilderFactory to create a DocumentBuilder instance.
Utilize the createElementNS method to create elements that are associated with specific namespaces.
Transform the DOM into an XML format using Transformer API.

Common Mistakes

Mistake: Not defining the namespace URI correctly.

Solution: Ensure that the namespace URI used in createElementNS matches the intended schema.

Mistake: Forgetting to append the elements to the document.

Solution: Always append the created elements to their parent elements before transforming.

Mistake: Neglecting to handle exceptions properly.

Solution: Wrap your code in try-catch blocks to manage potential parsing or IO exceptions.

Helpers

Java XML
creating XML in Java
Java namespaces in XML
DOM XML Java
XML document creation Java