Question

I have a problem with my custom JSON deserializer.
I use Jackson to map JSON to Java and back. In some cases I need to write my own mapping.

I have an object (filter), which contains a set of another object(metaInfoClass). I try to deserialize the filter with Jackson, but I implemented an own deserializer for the inner object.
The JSON looks like this:

{     
 "freetext":false,
 "cityName":null,
 "regionName":null,
 "countryName":null,
 "maxResults":50,
 "minDate":null,
 "maxDate":null,
 "metaInfoClasses":
  [
     {
      "id":31,
      "name":"Energy",
      "D_TYPE":"Relevance"
     }
  ],
 "sources":[],
 "ids":[]
}

My deserializer just works fine, it finds all the fields etc.
The problem is, that somehow (no idea why) the deserializer gets invoked on the rest of the JSON string, so the sources token is getting processed, and so on.
This is very weird, since I don’t want to deserialize the big object, but only the inner metaInfoClass.

Even more weird: the CollectionDeserializer class keeps calling my deserializer with the json string even after it is ended. So nothing really happens, but the method gets called.

Any idea?

Thanks a lot!

Answer 1

I was able to find a solution.
I modified the implementation (in the deserialize method) to use to following code:

JsonNode tree = parser.readValueAsTree();
Iterator<Entry<String, JsonNode>> fieldNameIt = tree.getFields();

while (fieldNameIt.hasNext()) {
  Entry<String, JsonNode> entry = fieldNameIt.next();
  String key = entry.getKey();
  String value = entry.getValue().getTextValue();

  // ... custom code here
}

So with this approach, it was parsing only the right piece of the code and it’s working right now.