How to control encoding with Jackson XmlMapper?

Question

I can't find a(n obvious) way to change the encoding for serialized XML from the default UTF-8 to ISO-8859-1. I read the Usage Guide, which makes me think that there must be a way using XMLOutputFactory with XmlFactory to achieve this, but I can't see a way to configure any of those factories to use another encoding by default, there's only createXMLEventWriter where I could pass in an encoding.

I know how to generate the XML declaration using ToXmlGenerator.Feature.WRITE_XML_DECLARATION. So what I need is a declaration like this:

<?xml version='1.0' encoding='ISO-8859-1'?>

And of course the content should be encoded in ISO-8859-1, too.

Answer 1

In the ToXmlGenerator source code, you'll find that UTF-8 is hard coded:

if (Feature.WRITE_XML_1_1.enabledIn(_formatFeatures)) {
    _xmlWriter.writeStartDocument("UTF-8", "1.1");
} else if (Feature.WRITE_XML_DECLARATION.enabledIn(_formatFeatures)) {
    _xmlWriter.writeStartDocument("UTF-8", "1.0");
} else {
    return;
}

Once ToXmlGenerator is final there might not be an easy way to handle it. I've submitted an issue in the jackson-dataformat-xml project.

---

If you stick to JAXB, you can control the value of the encoding attribute using Marshaller.JAXB_ENCODING:

Marshaller marshaller = jaxbContext.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.setProperty(Marshaller.JAXB_ENCODING, "ISO-8859-1");
marshaller.marshal(foo, System.out);

See this answer.