Update partial XML mapping to bean

Question

I need to map an xml file subset of nodes to a Java Bean.

For example map

<data>
    <field1>Value</field1>
    <field2>Value</field2>
    <field3>Value</field3>
    <field4>Value</field4>
    <field5>Value</field5>
</data>

to

public class DataBean {
    private String field2;
    private String field5;
    // ...getter/setter
}

then manipulate the bean and update the source xml file without loosing elements that are not mapped. How can I use to do it? What library?

Thanks for help, Maurizio

Answer 1

Note: I'm the EclipseLink JAXB (MOXy) lead an a member of the JAXB 2 (JSR-222) expert group.

Below is how this can be done with MOXy's implementation of the JAXB Binder:

DataBean

package forum9988170;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name="data")
public class DataBean {

    private String field2;
    private String field5;

    public String getField2() {
        return field2;
    }

    public void setField2(String field2) {
        this.field2 = field2;
    }

    public String getField5() {
        return field5;
    }

    public void setField5(String field5) {
        this.field5 = field5;
    }

}

jaxb.properties

To specify MOXy as your JAXB provider you need to add a file named jaxb.properties in the same package as your domain classes with the following entry,

javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory

Demo

package forum9988170;

import java.io.File;
import javax.xml.bind.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Node;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(DataBean.class);

        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        File xml = new File("src/forum9988170/input.xml");
        Document document = db.parse(xml);

        Binder<Node> binder = jc.createBinder();
        DataBean dataBean = (DataBean) binder.unmarshal(document);
        dataBean.setField2("NEW FIELD 2");
        dataBean.setField5("NEW FIELD 5");
        binder.updateXML(dataBean);

        TransformerFactory tf = TransformerFactory.newInstance();
        Transformer t = tf.newTransformer();
        DOMSource source = new DOMSource(document);
        StreamResult result = new StreamResult(System.out);
        t.transform(source, result);
    }

}

Output

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<data>
    <field1>Value</field1>
    <field2>NEW FIELD 2</field2>
    <field3>Value</field3>
    <field4>Value</field4>
    <field5>NEW FIELD 5</field5>
</data>

For More Information

• http://blog.bdoughan.com/2010/09/jaxb-xml-infoset-preservation.html
• http://blog.bdoughan.com/2012/01/how-does-jaxb-compare-to-xmlbeans.html
• http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html

Answer 2

If you decide what is in structure xml then you may use XStream (http://x-stream.github.io/) to serialize and deserialize. But if you only deserialize from xml to bean (from foreign format), then you should use Smooks (http://www.smooks.org/).

Both of these libraries are very light in contrast to JAXB. JAXB is not flexible and requires that creating XML Schema. I do not recommend, because you lose more time than on creating a simple DOM parse.

JAXB is very academic. Example: many of "SOAP envelopes" is not fully described by WSDL documents, but adds some xml into WSDL field (in a simple text field). In such a case, you lose a lot of time to create a JAXB infrastructure...

Of course this is just my personal opinion. But remember these two tools and try to use them. You'll see that it really worth.