Gson Serialize field only if not null or not empty

I have requirement where I need to convert java object to json.

I am using Gson for that but i need the converter to only serialize the non null or not empty values.

For example:

//my java object looks likeclass TestObject{    String test1;    String test2;    OtherObject otherObject = new OtherObject();}

now my Gson instance to convert this object to json looks like

Gson gson = new Gson();TestObject obj = new TestObject();obj.test1 = "test1";obj.test2 = "";String jsonStr = gson.toJson(obj);println jsonStr;

In the above print, the result is

{"test1":"test1", "test2":"", "otherObject":{}}

Here i just wanted the result to be

{"test1":"test1"}

Since the test2 is empty and otherObject is empty, i don't want them to be serialized to json data.

Btw, I am using Groovy/Grails so if there is any plugin for this that would be good, if not any suggestion to customize the gson serialization class would be good.