Access attribute of internal element in the most s

问题:

Is there any way to do mapping with single java bean for such simple xml:

<item lang="en">
   <item-url>some url</item-url>
   <parent id="id_123"/>
</item>

I've tried something like this:

@XmlRootElement( name = "item" )
public class Item {

    @XmlElement( name = "item-url" )
    private String url;

    @XmlAttribute( name = "parent/@id" )
    // Of course XPath doesn't work here, but it would be great...
    private String parentId;
}

In other words - how can I access attribute of internal element without creating of corresponding bean?

回答1:

You could use an XmlAdapter:

ParentIdAdapter

public class ParentIdAdapter extends XmlAdapter<ParentIdAdapter.AdaptedParentId, String> {

    public String unmarshal(AdaptedParentId value) {
        return value.id;
    }

    public AdaptedParentId marshal(String value) {
        AdaptedParentId adapted = new AdaptedParentId();
        adapted.id = value;
        return adapted;
    }

    public static class AdaptedParentId {
        @XmlAttribute
        public String id;
    }

}

Item

@XmlRootElement( name = "item" )
public class Item {

    @XmlElement( name = "item-url" )
    private String url;

    @XmlElement( name = "parent" )
    @XmlJavaTypeAdapter(ParentIdAdapter.class)
    private String parentId;
}

---

If you are using EclipseLink MOXy as your JAXB provider then you could leverage the @XmlPath extension to do the following:

@XmlRootElement( name = "item" )
public class Item {

    @XmlElement( name = "item-url" )
    private String url;

    @XmlPath("parent/@id")
    private String parentId;
}

回答2:

As I didn't want to create redundant classes in my package, the best solution I've found is:

@XmlRootElement( name = "item" )
public class Item {

    @XmlRootElement( name = "parent" )
    private static class ParentIdWrapper {
        @XmlAttribute( name = "id" )
        public String id;
    }

    @XmlElement( name = "item-url" )
    private String url;

    @XmlElement( name = "parent" )
    private ParentIdWrapper parentIdWrap;

    public String getParentId() {
        return this.parentIdWrap.id;
    }
}