Deserializing JSON with multiple types in one field

Question

I would like to deserialize JSON (with Jackson 1.9.11 and RestTemplate 1.0.1), in which one field may have more type meanings, for example:

    {\"responseId         


        

Answer 1

The only way to achieve that is to use a custom deserializer.

Here is an example:

ObjectMapper mapper = new ObjectMapper();
SimpleModule testModule = new SimpleModule("MyModule", new Version(1, 0, 0, null));
testModule.addDeserializer(Response.class, new ResponseJsonDeserializer());
mapper.registerModule(testModule);

And here is how to write (how I would write it at least) the deserializer:

class ResponseJsonDeserializer extends JsonDeserializer<Response>  {
  @Override
  public Responsedeserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException {
    Response response = new Response();
    if(jp.getCurrentToken() == JsonToken.VALUE_STRING) {
        response.setError(jp.getText());
    } else {
       // Deserialize object
    }
    return response;
  }
}

class Response {
   private String error;
   private Object otherObject; // Use the real type of your object

   public boolean isError() {
      return error != null;
   }

   // Getters and setters

}