JAXB use String as it is

Question

I use REST and i was wondering if i can tell jaxb to insert a string field "as-it-is" into the outgoing xml. Certainly i count unpack it before returning, but i would like to save this step.

@XmlRootElement(name="unnestedResponse")
public class Response{
 @Insert annotation here ;-)
 private String alreadyXml;
 private int otherDate; ...
}

Is there a possability to tell JAXB to just use the String as it is without escapting? I want that the client does not have to parse my response and then parse this field.

greetings, m

Answer 1

You can use the @XmlAnyElement and specify a DomHandler to keep a portion of the XML document as a String.

Customer

import javax.xml.bind.annotation.*;

@XmlRootElement
public class Customer {

    private String bio;

    @XmlAnyElement(BioHandler.class)
    public String getBio() {
        return bio;
    }

    public void setBio(String bio) {
        this.bio = bio;
    }

}

BioHandler

import java.io.*;
import javax.xml.bind.ValidationEventHandler;
import javax.xml.bind.annotation.DomHandler;
import javax.xml.transform.Source;
import javax.xml.transform.stream.*;

public class BioHandler implements DomHandler<String, StreamResult> {

    private static final String BIO_START_TAG = "<bio>";
    private static final String BIO_END_TAG = "</bio>";

    private StringWriter xmlWriter = new StringWriter();

    public StreamResult createUnmarshaller(ValidationEventHandler errorHandler) {
        return new StreamResult(xmlWriter);
    }

    public String getElement(StreamResult rt) {
        String xml = rt.getWriter().toString();
        int beginIndex = xml.indexOf(BIO_START_TAG) + BIO_START_TAG.length();
        int endIndex = xml.indexOf(BIO_END_TAG);
        return xml.substring(beginIndex, endIndex);
    }

    public Source marshal(String n, ValidationEventHandler errorHandler) {
        try {
            String xml = BIO_START_TAG + n.trim() + BIO_END_TAG;
            StringReader xmlReader = new StringReader(xml);
            return new StreamSource(xmlReader);
        } catch(Exception e) {
            throw new RuntimeException(e);
        }
    }

}

For More Information

• http://blog.bdoughan.com/2011/04/xmlanyelement-and-non-dom-properties.html

Answer 2

Following bdoughan's answer did not work for me as I encountered errors during marshalling when the text contained the '& character (e.g. in URLs or when using HTML entities such as e.g. " ").

I was able to resolve this by changing the custom DomHandler's marshal method to

public Source marshal(String et, ValidationEventHandler veh) {
    Node node = new SimpleTextNode(et);
    return new DOMSource(node);
}

where SimpleTextNode implements the Node interface as follows:

class SimpleTextNode implements Node {
    
    String nodeValue = "";
    
    @Override    
    public SimpleTextNode(String nodeValue) {
        this.nodeValue = nodeValue;
    }
    
    @Override
    public short getNodeType() {
        return TEXT_NODE;
    }

    // the remaining methods of the Node interface are not needed during marshalling
    // you can just use the code template of your IDE...

    ...
}

PS: I would have loved to leave this as a comment to bdoughan's answer, but unfortunately I have way too little reputation :-(