How to deserialize XML node to pojo in Java?

Question

Say i have a very large XML file that contains thousands of nodes that contain all kinds of details, something like:

<Document>
    <Header>
    </Header>
    <Whatever>
        <Person>
            <Name>John Doe</Name>
            <Age>30</Age>
        </Person>
        <Person>
            <Name>Jane Doe</Name>
            <Age>30</Age>
        </Person>
        ...
    </Whatever>
</Document>

I want to stream the xml file, and each time it hits a Person node, it should give me a Person pojo. With StAX i can do that by creating the pojo manually, but i'm betting there are libraries out there that do that for me.

Answer 1

Define a class like:

@XmlRootElement
public class Person {

    @XmlElement(name = "Name")
    String name;

    @XmlElement(name = "Age")
    int age;
}

@XmlRootElement
public class Header {    
}

@XmlRootElement
public class Document {

    @XmlElement(name = "Header")
    Header header;

    @XmlElementWrapper(name = "Whatever")
    @XmlElement(name = "person")
    List<Person> people;
}

After use JAXB for unmarshalling xml to object.

JAXBContext jaxbContext = JAXBContext.newInstance(Document.class);
Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
Document document = (Document) jaxbUnmarshaller.unmarshal(file);

List<Person> people = document.getPeople();