java - How to configure MappingJacksonHttpMessageConverter while using spring annotation-based configuration?

Question

I was unreasonable enough to went into configuring spring beans via annotations and not pure xml beans and now I'm facing the consequences.

I configure REST channels using

<mvc:annotation-driven />

Now I want simply configure the MappingJacksonHttpMessageConverter to output to JSON only this fields that have non-null values. I've tried the following:

<bean id="jsonHttpMessageConverter"
    class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
    <property name="prefixJson" value="false" />
    <property name="supportedMediaTypes" value="application/json" />
    <property name="objectMapper">
        <bean class="org.codehaus.jackson.map.ObjectMapper">
            <property name="serializationInclusion" value="NON_NULL"/>
        </bean>
    </property>
</bean>

The beans gets created, but another instance of converter is created and used in channels. So I've tried the way with @Configuration and @Bean described in this Stackoverflow question, but still json serialization uses its own configuration.

Finally I've tried to inject the mapper via

@Autowired
private MappingJacksonHttpMessageConverter jacksonConverter;

but I've ended with NoSuchBeanDefinitionException. So now I'm out of options and therefore I'm asking for any ideas here. How to controll and configure the mapper used by framework?

Answer 1

Use the WebMvcConfigurer.configureMessageConverters() method:

Configure the HttpMessageConverters to use [...] If no message converters are added to the list, default converters are added instead.

With @Configuration you have:

@Configuration
class MvcConf extends WebMvcConfigurationSupport {
    protected void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(converter());
        addDefaultHttpMessageConverters(converters);
    }

    @Bean
    MappingJacksonHttpMessageConverter converter() {
        MappingJacksonHttpMessageConverter converter = new MappingJacksonHttpMessageConverter()
        //do your customizations here...
        return converter;
    }
}

Call to addDefaultHttpMessageConverters() is required because the defaults are not applied when using custom converters.

IMPORTANT NOTE You must remove @EnableWebMvc for your converters to be configured if you extend WebMvcConfigurationSupport.