Deserializing non-string map keys with Jackson

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After a day of searching, I came across a simpler way of doing it based on this question. The solution was to add the @JsonDeserialize(keyUsing = YourCustomDeserializer.class) annotation to the map. Then implement your custom deserializer by extending KeyDeserializer and override the deserializeKey method. The method will be called with the string key and you can use the string to build the real object, or even fetch an existing one from the database.

So first in the map declaration:

@JsonDeserialize(keyUsing = MyCustomDeserializer.class)
private Map<Verb, List<Verb>> similarVerbs;

Then create the deserializer that will be called with the string key.

public class MyCustomDeserializer extends KeyDeserializer {
    @Override
    public MyMapKey deserializeKey(String key, DeserializationContext ctxt) throws IOException, JsonProcessingException {
        //Use the string key here to return a real map key object
        return mapKey;
    }
}

Works with Jersey and Jackson 2.x

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