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.