NOTE #1: I am the EclipseLink JAXB (MOXy) lead and a member of the JAXB (JSR-222) expert group.
NOTE #2: The output that you are seeing matches what you have mapped with JAXB. For more information see:
REPRESENTING NULL AS AN EMPTY ELEMENT
If you want to represent null as an empty element, there are a couple of options.
Option #1 - Using the Standard JAXB APIs
DateAdapter
You could use an XmlAdapter
to change the way an instance of Date
is marshalled to XML. We will convert the date to an instance of a class that has one property mapped with @XmlValue
(see http://blog.bdoughan.com/2011/06/jaxb-and-complex-types-with-simple.html). The JAXB RI does not call the XmlAdapter
mechanism for null values, so you will need to use a JAXB impl that does such as MOXy.
package forum11743306;
import javax.xml.bind.annotation.XmlValue;
import javax.xml.bind.annotation.adapters.XmlAdapter;
import javax.xml.datatype.XMLGregorianCalendar;
public class DateAdapter extends XmlAdapter<DateAdapter.AdaptedDate, XMLGregorianCalendar>{
@Override
public AdaptedDate marshal(XMLGregorianCalendar date) throws Exception {
AdaptedDate adaptedDate = new AdaptedDate();
adaptedDate.value = date;
return adaptedDate;
}
@Override
public XMLGregorianCalendar unmarshal(AdaptedDate adaptedDate) throws Exception {
return adaptedDate.value;
}
public static class AdaptedDate {
@XmlValue
public XMLGregorianCalendar value;
}
}
Root
The XmlAdapter
is referenced using the @XmlJavaTypeAdapter
annotation.
package forum11743306;
import javax.xml.bind.annotation.*;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
import javax.xml.datatype.XMLGregorianCalendar;
@XmlRootElement
public class Root {
private XMLGregorianCalendar xyzDate;
@XmlElement(name = "XYZDate", required=true, nillable = true)
@XmlJavaTypeAdapter(DateAdapter.class)
public XMLGregorianCalendar getXyzDate() {
return xyzDate;
}
public void setXyzDate(XMLGregorianCalendar xyzDate) {
this.xyzDate = xyzDate;
}
}
Option #2 - Using MOXy's @XmlNullPolicy Extension
MOXy offers an @XmlNullPolicy
extension that gives you some flexibility in how you represent null.
package forum11743306;
import javax.xml.bind.annotation.*;
import javax.xml.datatype.XMLGregorianCalendar;
import org.eclipse.persistence.oxm.annotations.*;
@XmlRootElement
public class Root {
private XMLGregorianCalendar xyzDate;
@XmlElement(name = "XYZDate", required=true, nillable = true)
@XmlNullPolicy(emptyNodeRepresentsNull = true, nullRepresentationForXml = XmlMarshalNullRepresentation.EMPTY_NODE)
public XMLGregorianCalendar getXyzDate() {
return xyzDate;
}
public void setXyzDate(XMLGregorianCalendar xyzDate) {
this.xyzDate = xyzDate;
}
}
Other Files
The following files can be used with either option to complete the example.
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 forum11743306;
import javax.xml.bind.*;
import javax.xml.datatype.DatatypeFactory;
import org.eclipse.persistence.Version;
public class Demo {
public static void main(String[] args) throws Exception {
JAXBContext jc = JAXBContext.newInstance(Root.class);
System.out.println(Version.getVersion());
System.out.println(jc.getClass());
Marshaller marshaller = jc.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
Root root = new Root();
root.setXyzDate(null);
marshaller.marshal(root, System.out);
root.setXyzDate(DatatypeFactory.newInstance().newXMLGregorianCalendar("2012-08-01"));
marshaller.marshal(root, System.out);
}
}
Output
2.4.0
class org.eclipse.persistence.jaxb.JAXBContext
<?xml version="1.0" encoding="UTF-8"?>
<root>
<XYZDate/>
</root>
<?xml version="1.0" encoding="UTF-8"?>
<root>
<XYZDate>2012-08-01</XYZDate>
</root>