XML to Java object with recursive child definition [closed]

Question

How can I convert this XML to Java objects?

 <template>
        <condition name="A">
            <li value="A">
                <condition name="B">
                    <li value="BB">Value B</li>
                    <li value="BBB">Value BBB</li>
                </condition>
            </li>
            <li>
                <condition name="C">
                    <li value="CC">Value CC</li>
                    <li value="CCC">Value CCC</li>
                    <li>
                        <condition name="D">
                            <li value="DD">Value DD</li>
                            <li value="DDD">Value DDD</li>
                         </condition>
                    </li>
                </condition>
            </li>
        </condition>
    </template>

Condition must have Li tag and li tag might have another condition and that condition will have li that might have another condition tag.

Answer 1

You need to model the XML elements by corresponding Java classes with some @Xml... annotations. This is fairly straight-forward. The fact that there is recursion involved does not raise any additional problems.

A class modeling the <template> root element (with nested <condition> element):

@XmlRootElement(name = "template")
@XmlAccessorType(XmlAccessType.FIELD)
public class Template {

    @XmlElement(name = "condition")
    private Condition condition;

    // getters and setters
}

A class modeling the <condition> element (with nested <li> elements):

@XmlAccessorType(XmlAccessType.FIELD)
public class Condition {

    @XmlAttribute(name = "name")
    private String name;

    @XmlElement(name = "li")
    private List<ListItem> listItems;

    // getters and setters
}

A class modeling the <li> element (with nested <condition> element):

@XmlAccessorType(XmlAccessType.FIELD)
public class ListItem {

    @XmlAttribute(name = "value")
    private String value;

    @XmlElement(name = "condition")
    private Condition condition;

    // getters and setters
}

You can test all these classes with a conversion XML -> Java -> XML like this:

JAXBContext context = JAXBContext.newInstance(Template.class);
Unmarshaller unmarshaller = context.createUnmarshaller();
Template template = (Template) unmarshaller.unmarshal(new File("template.xml"));
Marshaller marshaller = context.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(template, System.out);