Can I get MOXy to not output an attribute when generating json?

Question

An instance of my JAXB Object model contains an attribute that I want output when I generate Xml for the instance but not when I generate json

i.e I want

Answer 1

Since your JSON binding is slightly different from your XML binding I would use EclipseLink JAXB (MOXy)'s external mapping file.

oxm.xml

In the external mapping file we will mark the type field as transient.

ReleaseGroup

Below is the domain model I'll use for this example. Note how the type property is annotated with @XmlAttribute.

package forum383861;

import javax.xml.bind.annotation.*;

@XmlRootElement(name="release-group")
@XmlAccessorType(XmlAccessType.FIELD)
public class ReleaseGroup {

    @XmlAttribute
    String type;

    String title;

}

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

Since the XML and JSON representations are different we'll create separate JAXBContexts for them. For the JSON one we'll leverage MOXy's external mapping file.

package forum383861;

import java.util.*;
import javax.xml.bind.*;
import org.eclipse.persistence.jaxb.JAXBContextProperties;

public class Demo {

    public static void main(String[] args) throws Exception {
        ReleaseGroup rg = new ReleaseGroup();
        rg.type = "Album";
        rg.title = "Fred";

        // XML
        JAXBContext xmlJC = JAXBContext.newInstance(ReleaseGroup.class);
        Marshaller xmlMarshaller = xmlJC.createMarshaller();
        xmlMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        xmlMarshaller.marshal(rg, System.out);

        // JSON
        Map properties = new HashMap(2);
        properties.put(JAXBContextProperties.OXM_METADATA_SOURCE, "forum383861/oxm.xml");
        properties.put(JAXBContextProperties.MEDIA_TYPE, "application/json");
        JAXBContext jsonJC = JAXBContext.newInstance(new Class[] {ReleaseGroup.class}, properties);
        Marshaller jsonMarshaller = jsonJC.createMarshaller();
        jsonMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        jsonMarshaller.marshal(rg, System.out);
    }

}

Output

Below is the output from running the demo code:

   

{
   "release-group" : {
      "title" : "Fred"
   }
}