necromancer necromancer - 4 months ago 33
JSON Question

How to extract ObjectMapper from JAX-RS Client?

I am using Jersey JAX-RS client (version 2.0). I know it is using a Jackson ObjectMapper to generate and parse JSON. I want to use that same object to generate JSON for some java classes so that I can write them to a log.

I know I can create a new instance of ObjectMapper but I prefer to request Jersey Client to give me a reference to the one it is using. How can I do this? Jersey 2.0 is aware of Jackson because it includes a JacksonFeature class that is used to configure the Jackson feature in the first place.

Answer

I solved this by adding the following static members:

  private static JacksonJsonProvider jackson_json_provider = new JacksonJaxbJsonProvider()
      .configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false)
      .configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS, false);
  private static ObjectMapper object_mapper = jackson_json_provider.locateMapper(
      Object.class, MediaType.APPLICATION_JSON_TYPE);
  private static Client client = ClientBuilder.newClient().register(jackson_json_provider);

Note that the second declaration is not needed just to configure FAIL_ON_UNKNOWN_PROPERTIES or FAIL_ON_EMPTY_BEANS; I use object_mapper for some other reasons.