Jackson json deserialization, with root element from json

Question

I am having a question with Jackson that I think should be simple to solve, but it is killing me.

I have a java POJO class that looks like this (with getters and setters)

@JsonRootName(value = "notificacion")
public class NotificacionDTO extends AbstractDTO {

@JsonProperty(required=true)
private Integer instalacion;

@JsonProperty(required=true)
private Integer tipoNotificacion;

@JsonProperty(required=true)
private String mensaje;
}

Here is the AbstractDTO

public abstract class AbstractDTO implements Serializable {

public void validate() {
    Field[] declaredFields = this.getClass().getDeclaredFields();

    for (Field field : declaredFields) {
        if (field.isAnnotationPresent(JsonProperty.class)){
            if (field.getAnnotation(JsonProperty.class).required() && this.isNullParameter(field)) {
                throw new RuntimeException(String.format("El parametro %s es null o no esta presente en el JSON.", field.getName()));
            }
        }
    }
}

private boolean isNullParameter(Field field) {
    try {
        field.setAccessible(true);
        Object value = field.get(this);

        if (value == null) {
            return true;
        } else if (field.getType().isAssignableFrom(String.class)) {
            return ((String) value).isEmpty();
        }
    } catch (IllegalArgumentException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }
    return false;
}
}

I want to deserialize JSON that looks like this into a NotificacionDTO object:

{
  "notificacion":
  {
     "instalacion":"1",
     "tipoNotificacion":"2",
     "mensaje":"Un Mensaje"
  }
}

This is my EndPoint

@Controller
@RequestMapping("/notificacion")
public class NotificacionEndPoint extends AbstractEndPoint{

@Autowired
private NotificacionService service;

@RequestMapping(value = {"", "/"}, method = RequestMethod.POST)
@ResponseStatus(HttpStatus.CREATED)
public void addNotification(@RequestBody NotificacionDTO notification) throws JsonParseException, JsonMappingException, IOException {
        this.log.info("[POST RECEIVED] = " + notification);

        notification.validate();

        this.service.addNotification(notification);
}
}

I hava a custom ObjectMapper with this

public class JsonObjectMapper extends ObjectMapper {

public JsonObjectMapper() {
    super();

    this.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true);
}
}

When i POST i'm getting this error

Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException:  Unrecognized field "notificacion" (class ar.com.tecnoaccion.services.notificacion.NotificacionDTO), not marked as ignorable (3 known properties: , "tipoNotificacion", "instalacion", "mensaje"])
at [Source: org.apache.catalina.connector.CoyoteInputStream@1c1f3f7; line: 3, column:  5] (through reference chain: ar.com.tecnoaccion.services.notificacion.NotificacionDTO["notificacion"])

I try to add this to my DTO

 @JsonIgnoreProperties(ignoreUnknown = true)

but when i validate my DTO with the method validate all the dto's attributes are null and i get this error:

 java.lang.RuntimeException: El parametro instalacion es null o no esta presente en el JSON.

i am using jackson 2.2.3 and spring 3.2.1

thank you.

Answer 1

the simple answer is to post

{
 "instalacion":"1",
 "tipoNotificacion":"2",
 "mensaje":"Un Mensaje"
}

instead of

{
 "notificacion":
  {
   "instalacion":"1",
   "tipoNotificacion":"2",
   "mensaje":"Un Mensaje"
  }
}