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Pranav Pal
Pranav Pal

Reputation: 275

XML to Object conversion in Java specifying element-to-class mapping declaratively

I want to convert XML to Java objects. But I do not wish to hard code the mapping between XML tags and Java classes in the code, like for example using JAXB annotations or XStream.alias() method.

How do I achieve this?

Thanks!

Upvotes: 1

Views: 3857

Answers (2)

bdoughan
bdoughan

Reputation: 148977

Note: I'm the EclipseLink JAXB (MOXy) lead and a member of the JAXB (JSR-222) expert group.

In the EclipseLink MOXy implementation of JAXB we offer an external mapping document that can be used as an alternative to the standard annotations.

oxm.xml

Below is a sample mapping document.

<?xml version="1.0"?>
<xml-bindings
    xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm"
    package-name="blog.bindingfile">
    <xml-schema
        namespace="http://www.example.com/customer"
        element-form-default="QUALIFIED"/>
    <java-types>
        <java-type name="Customer">
            <xml-root-element/>
            <xml-type prop-order="firstName lastName address phoneNumbers"/>
            <java-attributes>
                <xml-element java-attribute="firstName" name="first-name"/>
                <xml-element java-attribute="lastName" name="last-name"/>
                <xml-element java-attribute="phoneNumbers" name="phone-number"/>
            </java-attributes>
        </java-type>
        <java-type name="PhoneNumber">
            <java-attributes>
                <xml-attribute java-attribute="type"/>
                <xml-value java-attribute="number"/>
            </java-attributes>
        </java-type>
    </java-types>
</xml-bindings>

Demo

Below is an example of how to specify the external mapping document when bootstrapping a JAXBContext.

package blog.bindingfile;

import java.io.File;
import java.util.*;
import javax.xml.bind.*;
import org.eclipse.persistence.jaxb.JAXBContextFactory;

public class Demo {

    public static void main(String[] args) throws Exception {
        Map<String, Object> properties = new HashMap<String, Object>(1);
        properties.put(JAXBContextFactory.ECLIPSELINK_OXM_XML_KEY, "blog/bindingfile/binding.xml");
        JAXBContext jc = JAXBContext.newInstance("blog.bindingfile", Customer.class.getClassLoader() , properties);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        Customer customer = (Customer) unmarshaller.unmarshal(new File("src/blog/bindingfile/input.xml"));

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(customer, System.out);
    }

}

For More Information

Upvotes: 1

Evgeniy Dorofeev
Evgeniy Dorofeev

Reputation: 135992

Then you should choose an XML parser and design your own unmarshaller. On the other hand JAXB can unmarshall xml into a Java bean without annotations, see this code, it works

public class Test {
    private String e1;

    public String getE1() {
        return e1;
    }

    public void setE1(String e1) {
        this.e1 = e1;
    }

    public static void main(String[] args) throws Exception {
        String xml = "<Test><e1>test</e1></Test>";
        Test t = JAXB.unmarshal(new StringReader(xml), Test.class);
        System.out.println(t.getE1());
    }
}

Upvotes: 2

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