Jackson XML Parsing

Question

Jackson 2.2.3

First, please excuse the stupid mistakes, I'm on a disconnected network, so I had to retype manually)

I have the following XML:

<orgs>
    <org name="Test1">
        <item>a</item>
        <item>b</item>
    </org>
    <org name="Test2">
        <item>c</item>
        <item>d</item>
        <item>e</item>
    </org>
</orgs>

I have the following class to parse this:

@XmlRootElement(name = "orgs")
@XmlAccessorType(XmlAccessType.FIELD)
public class XmlOrgElements {

    private List<Org> orgs;

    public List<Org> getOrgs() {
        return orgs;
    }

    public void setOrg(List<Org> orgs) {
        this.orgs = orgs;
    }

    public class Org {
        @JacksonXmlProperty(isAttribute = true)
        private String name;
        private List<Item> items;

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public List<Item> getItems() {
            return items;
        }

        public void setName(List<Item> items) {
            this.items = items;
        }
    }

    public class Item {
        @JacksonXmlText
        private String item;

        public String getItem() {
            return item;
        }

        public void setItem(String item) {
            this.item = item;
        }
    }
}

But all I'm getting back is "orgs=null". Does anyone know why?

Answer 1

You need to enable unwrapped handling for lists; default is to use "wrapped" format. The best way to diagnose this problem is to start with Java objects, serialize as XML, and see what the output format is. This gives an idea of how structure differs.

If you want to default to unwrapped style, you can use:

JacksonXmlModule module = new JacksonXmlModule();
module.setDefaultUseWrapper(false);
mapper.registerModule(module);

There is also an annotation @JacksonXmlElementWrapper:

public class Bean {
  @JacksonXmlElementWrapper(useWrapping=false)
  public List<Stuff> entry;
}

to change behavior on per-list-property basis.