How to not send an empty collection in jackson

Question

I have an object that is curently being serialized to:

{
  \"label\" : \"label\",
  \"proxyIds\" : [ ],
  \"childIds\" : [ 161, 204, 206, 303, 311 ],
  \"act         


        

Answer 1

Since Jackson 2.0.0 (25-Mar-2012), you can also use the @JsonInclude annotation to control this on a per-field or per-class basis.

public class MyObject {

    @JsonInclude(Include.NON_EMPTY)
    private List<Integer> proxyIds;

    ...
}

Answer 2

This may be a long shot but how about using Inclusions and defining NON_DEFAULT as the inclusion property. The docs say:

"Value that indicates that only properties that have values that differ from default settings (meaning values they have when Bean is constructed with its no-arguments constructor) are to be included."

So if the default value is an empty array it should skip it.

Something like:

ObjectMapper mapper = new ObjectMapper();
mapper.getSerializationConfig().setSerializationInclusion(Inclusion.NON_DEFAULT);


public class Test {
     String[] array = { };
     ....
}

http://jackson.codehaus.org/1.1.2/javadoc/org/codehaus/jackson/map/annotate/JsonSerialize.Inclusion.html