Question

How I can retrieve null value, when unmarshalling, if inside XML attribute value is empty ? Now I make inside my getters checking for null :

public String getLabel() {
    if (label.isEmpty()) {
        return null;
    }
    else {
        return label;
    }
}

But may be exist some other, more elegant way?

Thanks.

Answer 1

I think your XML looks more or less like this:

    <myElement></myElement>

This, unfortunately, means, that you are passing an empty string.

If you want to pass null you have two options:

1. Do not pass this tag at all (your XML should not contain <myElement/> tag at all).
2. Use xsi:nil.

If using xsi:nil, first you have to declare your xml element (in XSD file) as nilable, like this:

    <xsd:element name="myElement" nillable="true"/>

Then, to pass the null value inside XML do this:

    <myElement xsi:nil="true"/>

or this:

    <myElement xsi:nil="true"></myElement>

This way, JAXB knows, that you are passing null instead of an empty String.