Java – JSON does not contain properties of nested objects

I have the following courses:

public class Container {
    private String name;
    private Data data;
}

public class Data {
    private Long id;
}

When I use Jackson to serialize container classes, I get

{"name":"Some name","data":{"id":1}}

But what I need is:

{"name":"Some name","id":1}

Can I (without adding the container. Getdataid () method)? If so, what should I do?

to update

I tried to create a custom jsonserializer < data > but the result was the same as before

public class JsonDataSerializer extends JsonSerializer<Data> {

    private static Logger logger = Logger.getLogger(JsonDataSerializer.class);

    @Override
    public void serialize(Data value,JsonGenerator jgen,SerializerProvider provider)
            throws IOException,JsonProcessingException {

        Long id = (value.getId() == null) ? 0l : value.getId();
        jgen.writeStartObject();
        jgen.writeNumberField("id",id);
        jgen.writeEndObject();
        logger.debug("Data id " + id + " serialized to JSON.");       
    }
}

I also tried to add the @ jsonserialize annotation on the data class, and then add getters in the container class As mentioned earlier, there was no success My serializer is used to log messages

Update 2

When I delete writestartobject() and writeendobject(), then no JSON is returnsd, only HTTP status 500 error and no exception is thrown, except that I found it in the debugging output

DEBUG: org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerExceptionResolver - Resolving exception from handler [com.example.DataController@16be8a0]: org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Can not write a field name,expecting a value; nested exception is org.codehaus.jackson.JsonGenerationException: Can not write a field name,expecting a value
DEBUG: org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver - Resolving exception from handler [com.example.DataController@16be8a0]: org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Can not write a field name,expecting a value
DEBUG: org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver - Resolving exception from handler [com.example.DataController@16be8a0]: org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Can not write a field name,expecting a value

Solution

Jackson 1.9 has introduced the JSON unwrapped annotation, which is what you're looking for