Force Jackson to add addional wrapping using annotations

jackson, java

Solution

On workaround: you don't absolutely need those getters/setters, so could just have:

public class MessageWrapper {
  public Message message;
}

or perhaps add convenience constructor:

public class MessageWrapper {
  public Message message;
  @JsonCreator
  public MessageWrapper(@JsonProperty("message") Message m) { 
       message = m; 
  }
}

There is a way to add wrapping too; with 1.9 you can use `SerializationConfig.Feature.WRAP_ROOT_ELEMENT` and `DeserializationConfig.Feature.UNWRAP_ROOT_ELEMENT`. And if you want to change the wrapper name (by default it is simply unqualified class name), you can use `@JsonRootName` annotation

Jackson 2.0 adds further dynamic options via `ObjectReader` and `ObjectWriter`, as well as JAX-RS annotations.

Problem

I have the following class: ``` public class Message { private String text; public String getText() { return text; } public void setText(String text) { this.text = text; } } ``` When converting the instance to JSON using Jackson by default I get: ``` {"text":"Text"} ``` I would like to get: ``` {"message":{"text":"Text"}} ``` Is there any JAXB / Jackson annotation I can use to achieve my goal? As a workaround, I can wrap my class with another class: ``` public class MessageWrapper { private Message message; public Message getMessage() { return message; } public void setMessage(Message message) { this.message = message; } } ``` or a more generic solution: ``` public class JsonObjectWrapper<T> { /** * Using a real map to allow wrapping multiple objects */ private Map<String, T> wrappedObjects = new HashMap<String, T>(); public JsonObjectWrapper() { } public JsonObjectWrapper(String name, T wrappedObject) { this.wrappedObjects.put(name, wrappedObject); } @JsonAnyGetter public Map<String, T> any() { return wrappedObjects; } @JsonAnySetter public void set(String name, T value) { wrappedObjects.put(name, value); } } ``` Which can be used like so: ``` Message message = new Message(); message.setText("Text"); JsonObjectWrapper<Message> wrapper = new JsonObjectWrapper<Message>("message", message); ``` Is there any JAXB / Jackson annotation I can use to achieve my goal? Thanks.

Original source