Make #JsonView annotation on controller action include properties by default - json

Question

When you use Jackson's writerWithView any properties that don't have a #JsonView annotation on them are still serialised. However using #JsonView on a Spring MVC action seems to require #JsonView to be on every property.
If say we have the following model:
public class User {
private String username;
private String emailAddress;
public String getUsername() { return username; }
#JsonView(DetailView.class)
public String getEmailAddress() { return emailAddress; }
}
And DetailView extends BasicView, when I serialise with basic view I'd expect username to be serialised. This is what happens when we use writerWithView:
#RequestMapping(value = "/me", method = GET)
#ResponseBody
public String getMe() throws JsonProcessingException {
User user = getCurrentUser();
return objectMapper.writerWithView(BasicView.class).writeValueAsString(user);
}
However from Spring MVC 4.1 we can instead do the following:
#RequestMapping(value = "/me", method = GET)
#ResponseBody
#JsonView(BasicView.class)
public User getMe() throws JsonProcessingException {
return getCurrentUser();
}
The later causes the response to be {} rather than {username:"David"}. If we add #JsonView(BasicView.class) onto the getUsername() this works as expected.
Obviously we could go with the former or add #JsonView to everything, both of which are more verbose and error prone.
This looks a bit like MapperFeature.DEFAULT_VIEW_INCLUSION has been turned off, but explicitly enabling it doesn't seem to have worked.
Is there anyway to get around this?

Answer 1

MapperFeature.DEFAULT_VIEW_INCLUSION being disabled is indeed the problem, but unfortunately the Spring classes don't give an easy way to configure or replace the ObjectMapper used by the default message converters.
The neatest way I found to work around this was to extend DelegatingWebMvcConfiguration and override configureMessageConverters to populate the default converters and then overwrite the problematic MappingJackson2HttpMessageConverter:
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter;
import org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration;
import com.example.config.serialization.AllEncompassingFormHttpMessageConverterWithCustomObjectMapper;
import java.util.List;
#Configuration
#ComponentScan({/*...*/})
public class MyWebConfig extends DelegatingWebMvcConfiguration {
#Bean
public ObjectMapper objectMapper() {
ObjectMapper objectMapper = new ObjectMapper();
//...
return objectMapper;
}
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> messageConverters) {
super.configureMessageConverters(messageConverters);
if (messageConverters.isEmpty()) {
addDefaultHttpMessageConverters(messageConverters);
}
messageConverters.replaceAll(converter -> {
if (converter instanceof MappingJackson2HttpMessageConverter) {
return new MappingJackson2HttpMessageConverter(objectMapper());
} else if (converter instanceof AllEncompassingFormHttpMessageConverter) {
return new AllEncompassingFormHttpMessageConverterWithCustomObjectMapper(objectMapper());
}
return converter;
});
}
}
For completeness you may also want to substitute the AllEncompassingFormHttpMessageConverter, as above, with your own copy that also allows specification of an ObjectMapper. I've not included the AllEncompassingFormHttpMessageConverterWithCustomObjectMapper class here - it's a trivial copy of AllEncompassingFormHttpMessageConverter that forwards an ObjectMapper constructor parameter to the MappingJackson2HttpMessageConverter that it creates.