Question

I have this class:

Class B {
  private String D;
  private String E;
}

Using XStream, I would like to generate XML like this, where elements A and B are generated in the XML, even though they don’t exist in the java.:

<A>
        <B>
                <C>
                        <D/>
                        <E/>
                </C>
        </B>
</A>

Possible?

Answer 1

Note: I’m the EclipseLink JAXB (MOXy) lead and a member of the JAXB (JSR-222) expert group.

Since you are looking for an annotation based solution, you may be interested in the @XmlPath extension in MOXy.

B

The @XmlPath annotation allows you to specify your mapping as an XPath.

package forum11334385;

import javax.xml.bind.annotation.*;
import org.eclipse.persistence.oxm.annotations.XmlPath;

@XmlRootElement(name="A")
@XmlAccessorType(XmlAccessType.FIELD)
class B {

    @XmlPath("B/C/D/text()")
    private String D;

    @XmlPath("B/C/E/text()")
    private String E;

}

jaxb.properties

To specify MOXy as your JAXB provider you need to include a file called jaxb.properties in the same package as your domain model with the following entry (see: http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html).

javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory

Demo

package forum11334385;

import java.io.File;
import javax.xml.bind.*;

public class Demo {

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

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("src/forum11334385/input.xml");
        B b = (B) unmarshaller.unmarshal(xml);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(b, System.out);
    }

}

input.xml/Output

<?xml version="1.0" encoding="UTF-8"?>
<A>
   <B>
      <C>
         <D>Foo</D>
         <E>Bar</E>
      </C>
   </B>
</A>

For More Information

• http://blog.bdoughan.com/2010/07/xpath-based-mapping.html
• http://blog.bdoughan.com/2011/08/binding-to-json-xml-geocode-example.html
• http://blog.bdoughan.com/2011/03/map-to-element-based-on-attribute-value.html