How to customise the Jackson JSON mapper implicitly used by Spring Boot

Question

I m using Spring Boot  1 2 1   in a similar fashion as in their Building a RESTful Web Service tutorial   RestController public class EventController       RequestMapping  quot  events all quot      EventList events            return proxyService getAllEvents            So above  Spring MVC implicitly uses Jackson for serialising my EventList object into JSON  But I want to do some simple customisations to the JSON format  such as  setSerializationInclusion JsonInclude Include NON NULL   Question is  what is the simplest way to customise the implicit JSON mapper  I tried the approach in this blog post  creating a CustomObjectMapper  and so on  but the step 3   quot Register classes in the Spring context quot   fails  org springframework beans factory BeanCreationException     Error creating bean with name  jacksonFix   Injection of autowired dependencies failed     nested exception is org springframework beans factory BeanCreationException     Could not autowire method  public void com acme project JacksonFix setAnnotationMethodHandlerAdapter org springframework web servlet mvc annotation AnnotationMethodHandlerAdapter      nested exception is org springframework beans factory NoSuchBeanDefinitionException     No qualifying bean of type  org springframework web servlet mvc annotation AnnotationMethodHandlerAdapter       found for dependency  expected at least 1 bean which qualifies as autowire candidate for this dependency  Dependency annotations      It looks like those instructions are for older versions of Spring MVC  while I m looking for a simple way to get this working with latest Spring Boot

User · Accepted Answer

You can configure property inclusion  and numerous other settings  via application properties  spring jackson default-property-inclusion non null  There s a table in the documentation that lists all of the properties that can be used  If you want more control  you can also customize Spring Boot s configuration programatically using a Jackson2ObjectMapperBuilderCustomizer bean  as described in the documentation   The context   s Jackson2ObjectMapperBuilder can be customized by one or more Jackson2ObjectMapperBuilderCustomizer beans  Such customizer beans can be ordered  Boot   s own customizer has an order of 0   letting additional customization be applied both before and after Boot   s customization   Lastly  if you don t want any of Boot s configuration and want to take complete control over how the ObjectMapper is configured  declare your own Jackson2ObjectMapperBuilder bean   Bean Jackson2ObjectMapperBuilder objectMapperBuilder         Jackson2ObjectMapperBuilder builder   new Jackson2ObjectMapperBuilder           Configure the builder to suit your needs     return builder

User · Answer

I stumbled upon another solution  which is quite nice    Basically  only do step 2 from the blog posted mentioned  and define a custom ObjectMapper as a Spring  Component   Things started working when I just removed all the AnnotationMethodHandlerAdapter stuff from step 3     Component  Primary public class CustomObjectMapper extends ObjectMapper       public CustomObjectMapper             setSerializationInclusion JsonInclude Include NON NULL            configure DeserializationFeature FAIL ON UNKNOWN PROPERTIES  false              Works as long as the component is in a package scanned by Spring   Using  Primary is not mandatory in my case  but why not make things explicit    For me there are two benefits compared to the other approach    This is simpler  I can just extend a class from Jackson and don t need to know about highly Spring-specific stuff like Jackson2ObjectMapperBuilder  I want to use the same Jackson configs for deserialising JSON in another part of my app  and this way it s very simple  new CustomObjectMapper   instead of  new ObjectMapper

User · Answer

I know the question asking for Spring boot  but I believe lot of people looking for how to do this in non Spring boot  like me searching almost whole day   Above Spring 4  there is no need to configure MappingJacksonHttpMessageConverter if you only intend to configure ObjectMapper   You just need to do   public class MyObjectMapper extends ObjectMapper        private static final long serialVersionUID   4219938065516862637L       public MyObjectMapper             super            enable SerializationFeature INDENT OUTPUT                    And in your Spring configuration  create this bean    Bean  public MyObjectMapper myObjectMapper                 return new MyObjectMapper

User · Answer

The documentation states several ways to do this   If you want to replace the default ObjectMapper completely  define a  Bean of that type and mark it as  Primary  Defining a  Bean of type Jackson2ObjectMapperBuilder will allow you to customize both default ObjectMapper and XmlMapper  used in MappingJackson2HttpMessageConverter and MappingJackson2XmlHttpMessageConverter respectively

User · Answer

A lot of things can configured in applicationproperties  Unfortunately this feature only in Version 1 3  but you can add in a Config-Class   Autowired required   true  public void configureJackson ObjectMapper jackson2ObjectMapper        jackson2ObjectMapper setSerializationInclusion JsonInclude Include NON NULL        UPDATE  You must work on the ObjectMapper because the build  -method is called before the config is runs

User · Answer

When I tried to make ObjectMapper primary in spring boot 2 0 6 I got errors So I modified the one that spring boot created for me  Also see https   stackoverflow com a 48519868 255139   Lazy  Autowired ObjectMapper mapper    PostConstruct public ObjectMapper configureMapper         mapper setSerializationInclusion JsonInclude Include NON NULL       mapper enable DeserializationFeature ACCEPT EMPTY STRING AS NULL OBJECT        mapper configure DeserializationFeature FAIL ON UNKNOWN PROPERTIES  false       mapper configure SerializationFeature ORDER MAP ENTRIES BY KEYS  true        mapper configure MapperFeature ALLOW COERCION OF SCALARS  true       mapper configure MapperFeature SORT PROPERTIES ALPHABETICALLY  true        SimpleModule module   new SimpleModule        module addDeserializer LocalDate class  new LocalDateDeserializer         module addSerializer LocalDate class  new LocalDateSerializer         mapper registerModule module        return mapper

User · Answer

I found the solution described above with    spring jackson serialization-inclusion non null  To only work starting at the 1 4 0 RELEASE version of spring boot   In all other cases the config is ignored   I verified this by experimenting with a modification of the spring boot sample  spring-boot-sample-jersey

User · Answer

I am answering bit late to this question  but someone  in future  might find this useful  The below approach  besides lots of other approaches  works best  and I personally think would better suit a web application    Configuration  EnableWebMvc public class WebConfiguration extends WebMvcConfigurerAdapter         other configurations   Override     public void configureMessageConverters List lt HttpMessageConverter lt   gt  gt  converters            Jackson2ObjectMapperBuilder builder   new Jackson2ObjectMapperBuilder            builder serializationInclusion JsonInclude Include NON NULL           builder propertyNamingStrategy PropertyNamingStrategy CAMEL CASE TO LOWER CASE WITH UNDERSCORES           builder serializationInclusion Include NON EMPTY           builder indentOutput true  dateFormat new SimpleDateFormat  yyyy-MM-dd             converters add new MappingJackson2HttpMessageConverter builder build              converters add new MappingJackson2XmlHttpMessageConverter builder createXmlMapper true  build

User · Answer

The right way to add further configurations to the Spring Boot peconfigured ObjectMapper is to define a Jackson2ObjectMapperBuilderCustomizer  Else you are overwriting Springs configuration  which you do not want to lose    Configuration public class MyJacksonConfigurer implements Jackson2ObjectMapperBuilderCustomizer        Override     public void customize Jackson2ObjectMapperBuilder builder            builder deserializerByType LocalDate class  new MyOwnJsonLocalDateTimeDeserializer

User · Answer

spring jackson serialization-inclusion non null used to work for us  But when we upgraded spring boot version to 1 4 2 RELEASE or higher  it stopped working    Now  another property spring jackson default-property-inclusion non null is doing the magic   in fact  serialization-inclusion is deprecated  This is what my intellij throws at me      Deprecated  ObjectMapper setSerializationInclusion was deprecated in   Jackson 2 7   So  start using spring jackson default-property-inclusion non null instead

User · Answer

You can add a following method inside your bootstrap class which is annotated with  SpringBootApplication       Bean      Primary     public ObjectMapper objectMapper Jackson2ObjectMapperBuilder builder        ObjectMapper objectMapper   builder createXmlMapper false  build        objectMapper configure SerializationFeature WRITE DATES AS TIMESTAMPS  false       objectMapper configure SerializationFeature WRITE DATE TIMESTAMPS AS NANOSECONDS  false        objectMapper registerModule new JodaModule          return objectMapper

[java] How to customise the Jackson JSON mapper implicitly used by Spring Boot?

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