How to serialize only the ID of a child with Jackson

Question

Is there a built-in way to only serialize the id of a child when using Jackson (fasterxml.jackson 2.1.1)? We want to send an Order via REST which has a Pe

Answer 1

You can write a custom serializer like this:

public class ChildAsIdOnlySerializer extends StdSerializer {

  // must have empty constructor
  public ChildAsIdOnlySerializer() {
    this(null);
  }

  public ChildAsIdOnlySerializer(Class t) {
    super(t);
  }

  @Override
  public void serialize(Child value, JsonGenerator gen, SerializerProvider provider)
      throws IOException {
    gen.writeString(value.id);
  }

Then use it by annotating the field with @JsonSerialize:

public class Parent {
   @JsonSerialize(using = ChildAsIdOnlySerializer.class)
   public Child child;
}

public class Child {
    public int id;
}