Handling XMLElement nillable like JAXB · Issue #89 · FasterXML/jackson-dataformat-xml (original) (raw)

I cant find any way to make Jackson serialize the typical "xsi:nil"-Attribute that is defacto standard to represent NULL-Values in XML? Please correct me if i see this wrong ;-)

In JAXB this can be done easily by annotating a java-variable with: @xmlelement(nillable=true)

see also: http://blog.bdoughan.com/2012/04/binding-to-json-xml-handling-null.html

can/should Jackson do this?

here also a compare of JAXB and Jackson.

• jackson serializes NULL-values per default as
  • can be configured so NULL-values will not be serialized at all
• jackson deserializes missing elements as NULL
• jackson deserializes and for branch-nodes as NULL
• jackson deserializes and for leaf-nodes as NULL..
  but as soon as attributes (z.b. xsi:nil) are on the leaf-node, jackson
  seems to think its a branch-node instead and throws an exception
  while mapping it to an pojo
• JAXB does not serialize NULL-values per default
  • If fields are annotated with @nillable, the field will be serialized as <x xsi:nil="true/>
• JAXB deserializes missing elements as NULL
  • If fields are annotated with @nillable, will be deserialized as NULL
• JAXB deserializes or for branch-nodes by providing default-values for all contained
  leaf-nodes.
• JAXB deserializes or for leaf-nodes not as NULL-values but provides default-values (an integer will be 0 by default).

so it seems to me that the best way at the moment is not to serialize/deserialize NULL-values but just leave them out. The only bad thing about this is, that empty strings "" can not be represented...