JAX-B: dynamically generate element name from XMLAttribute

问题

I'm using JAX-B (v.2.2.12) to marshal a java objects tree. One of the classes to be marshalled is CaseObject:

public class CaseObject {
...
  @XmlAnyElement
  @XmlJavaTypeAdapter(ParameterAdapter.class)
  protected List <CaseObject> caseObjects;
...
}

The current xml represention after marshalling:

<caseObject id="1" name="someName" typeId="0">
         ...
        <caseObject id="29" key="someOtherName" typeId="12">
         ...
        </caseObject>
</caseObject>

The required target xml represention:

<someName id="1" name="someName" typeId="0">
         ...
        <someOtherNameid="29" key="someOtherName" typeId="12">
         ...
        </someOtherName>
</someName>

I've played around by extending @XmlAdapter using the following snippet (example from a blog):

    @Override
    public Element marshal(CaseObject caseObject) throws Exception {
    if (null == caseObject) {
        return null;
    }

    // 1. Build a JAXBElement
    QName rootElement = new QName(caseObject.getName());
    Object value = caseObject;
    Class<?> type = value.getClass();
    JAXBElement jaxbElement = new JAXBElement(rootElement, type, value);

    // 2.  Marshal the JAXBElement to a DOM element.
    Document document = getDocumentBuilder().newDocument();
    Marshaller marshaller = getJAXBContext(type).createMarshaller();

    // where the snake bites its own tail ...
    marshaller.marshal(jaxbElement, document);
    Element element = document.getDocumentElement();

    return element;
}

Question is: How to instrument JAX-B to dynamically generate Element names from a property(XMLAttribute) during marshalling?

回答1:

The following XMLAdapter works for me. Simply choose JAXBElement as the adapters ValueType. (use your concrete object as BoundType, of course.) This solution's precondition is, that the QName's value is a valid xml element name.

public class CaseObjectAdapter extends XmlAdapter<JAXBElement, CaseObject> {

@Override
public JAXBElement marshal(CaseObject caseObject) throws Exception {

    JAXBElement<CaseObject> jaxbElement = new JAXBElement(new QName(caseObject.methodThatReturnsAnElementName()), caseObject.getClass(), caseObject);

    return jaxbElement;
}

...

来源：https://stackoverflow.com/questions/37486280/jax-b-dynamically-generate-element-name-from-xmlattribute

标签

java

xml

jaxb