Question

Below is the xml I have to work with:

<watermarks identifier="X" hostname="X">
   <watermark type="XX" value="1234"/>
   <watermark type="YY" value="1234" />
</watermarks>

I just want to get a list of Watermark objects using JAXB without creating a new Watermarks class. Is it possible or should I have to create a Watermarks class which contains a list of Watermark objects ?

Thanks.

Answer 1

You could use a StAX (JSR-173) XMLStreamReader to parse the XML document (an implementation is included in the JDK/JRE since Java SE 6). Then you could advance it to advance to each watermark element and then have JAXB (JSR-222) unmarshal that.

Demo

Assuming the Watermark class is annotated with @XmlRootElement you could do the following.

import javax.xml.bind.*;
import javax.xml.stream.*;
import javax.xml.transform.stream.StreamSource;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Watermark.class);
        Unmarshaller unmarshaller = jc.createUnmarshaller();

        StreamSource source = new StreamSource("input.xml");
        XMLInputFactory xif = XMLInputFactory.newFactory();
        XMLStreamReader xsr = xif.createXMLStreamReader(source);
        xsr.nextTag(); // Advance to "watermarks" element
        xsr.nextTag(); // Advance to "watermark" element

        while(xsr.getLocalName().equals("watermark")) {
             Watermark object = (Watermark) unmarshaller.unmarshal(xsr);
             System.out.println(object);
             xsr.nextTag();
        }
    }

}

Full Example

• JAXB unmarshalling of "generic" real world documents

Generic List Wrapper Class

In my answer to the question below I provided an example of a generic list wrapper class that you may find useful.

• How to marshalling the muliptle object using jaxb