This is not a bug of Spring Data Rest it is actually the normal behaviour of the Jackson Serializer. Whenever you use the @JsonUnwrapped Annotation (as the Resource content field does) together with a custom Serializer the Jackson Serializer will explicitly write the field name (in this case content). Have a look at the UnwrappingBeanPropertyWriter for more details. Anyhow you have been on the right track using the UnwrappingBeanSerializer but the setup is slightly different then the usual Serializer registration. The following example should fix your problem:
@Override
protected void configureJacksonObjectMapper(ObjectMapper objectMapper) {
mapper.registerModule(new Module() {
@Override
public String getModuleName() {
return "my.module";
}
@Override
public Version version() {
return Version.unknownVersion();
}
@Override
public void setupModule(SetupContext context) {
context.addBeanSerializerModifier(new BeanSerializerModifier() {
@Override
public JsonSerializer<?> modifySerializer(SerializationConfig config, BeanDescription beanDesc, JsonSerializer<?> serializer) {
if(beanDesc.getBeanClass().equals(Order.class)) {
return new UnwrappingOrderSerializer((BeanSerializerBase) serializer, NameTransformer.NOP);
}
return serializer;
}
});
}
});
}
public class UnwrappingOrderSerializer extends UnwrappingBeanSerializer {
public UnwrappingBarSerializer(BeanSerializerBase src, NameTransformer transformer) {
super(src, transformer);
}
@Override
public JsonSerializer<Object> unwrappingSerializer(NameTransformer transformer) {
return new UnwrappingOrderSerializer(this, transformer);
}
@Override
protected void serializeFields(Object bean, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonGenerationException {
Order order = (Order) bean;
jgen.writeStringField("paid", order.isPaid();
}
@Override
public boolean isUnwrappingSerializer() {
return true;
}
}