java - JAXB Marshalling with null fields

Question

This is a pretty simple request, but I just didn't find a way to do it.

I'm basically trying to set up a role in JAXB which says that whenever an null field is encountered, instead of ignoring it in the output, set it to an empty value. So for the class :

@XMLRootElement
Class Foo {
   Integer num;
   Date date;
….
}

When this has been marshalled into the XML file if the date field is null, my output does not have that element in it. What I want to do is include all the fields in the output; and if they are null, replace them with - say a blank. So the output should be :

<foo>
  <num>123</num>
  <date></date>
</foo>

Thanks,

Jalpesh.

Answer 1

Thanks guys for your answers.

Chris Dail - I tried your approach, and it didn't really do what I wanted. JAXB was still ignoring my null values, in spite of defining a default value for my fields.

I did stumble across the answer after somebody in the Jersey forums pointed me to documentation section 2.2.12.8 No Value.

Basically, all I had to do was to add the following to my fields :

@XmlElement(nillable = true) 

Once I added that, JAXB would show up those fields when marshalling them to XML like this:

...
<num>5</num>
<date xsi:nil="true" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
....