Forcing Jackson to deserialize to specific primitive type

Question

I am serializing and deserializing following domain object to JSON using Jackson 1.8.3

public class Node {     private String key;     private Object value;     private List<Node> children = new ArrayList<Node>();     /* getters and setters omitted for brevity */ } 

Object is then serialized and deserialized using following code

ObjectMapper mapper = new ObjectMapper(); mapper.writeValue(destination, rootNode); 

And then later deserialized with

mapper.readValue(destination, Node.class); 

The original values of the object are either Strings, Doubles, Longs or Booleans. However, during serialization and deserialization Jackson transforms Long values (such as 4) to Integers.

How can I "force" Jackson to deserialize numeric non-decimal values to Long instead of Integer?

Answer 1

There is a new feature in Jackson 2.6 specifically for this case:

configure the ObjectMapper to use DeserializationFeature.USE_LONG_FOR_INTS

see https://github.com/FasterXML/jackson-databind/issues/504

cowtowncoder pushed a commit that closed this issue on May 19, 2015 Fix #504 and #797