Revisit Jackson support

[sdeleuze]

Spring Framework 7.0 introduces Jackson 3 support in parallel of the now deprecated Jackson 2 one.

More information can be found on the changes of migrating from Jackson 2 to Jackson 3 in the following links:

• Taking Jackson 3.0.0-rc1 for a spin
• Jackson 3.0.0-rc2 (minor update)
• Jackson 3.0.0-rc3
• Jackson 3.0.0-rc4
• Path to Jackson 3.0.0

The Jackson 3 changes with the biggest impact on Spring use-cases are:

• Jackson 3 uses a different package (tools.jackson) than Jackson 2 (com.fasterxml.jackson) except for jackson-annotation (@JsonView, @JsonTypeInfo) which keeps using com.fasterxml.jackson
• ObjectMapper#canDeserialize and ObjectMapper#canSerialize have been removed as they were not reliable, so Jackson 3 converters and codecs only test mime types and type resolution in their canXxx methods.
• The order of properties is now alphabetical by default (can be changed with MapperFeature.SORT_PROPERTIES_ALPHABETICALLY)
• Slashes are now escaped by default (can be changed with JsonWriteFeature.ESCAPE_FORWARD_SLASHES, impact ProblemDetail)
• Jackson 3 defaults are aligned with Spring ones:
  • MapperFeature.DEFAULT_VIEW_INCLUSION is disabled by default
  • DeserializationFeature.FAIL_ON_UNEXPECTED_VIEW_PROPERTIES is disabled by default

General:

• No Jackson 3 equivalent of Jackson2ObjectMapperBuilder is provided, the recommendation is to use JsonMapper.builder(), CBORMapper.builder(), etc.
• By default, Jackson modules discovered by MapperBuilder#findModules(java.lang.ClassLoader) are registered in converters and codecs
• org.springframework.http.converter.json.SpringHandlerInstantiator enabled by default in Spring MVC ->
  org.springframework.http.support.JacksonHandlerInstantiator now requires explicit configuration
• Jackson 3 support is configured if found in the classpath otherwise fallback to Jackson 2
• Jackson 2 support will be deprecated for removal (current plan is autodetection disabled in 7.1, and removal done in 7.2)

WebMVC:

• Switch from GenericHttpMessageConverter to SmartHttpMessageConverter which support hints
• Use hints instead of MappingJacksonValue and MappingJacksonInputMessage to support @JsonView and FilterProvider
• Introduction of RequestBodyAdvice#determineReadHints and ResponseBodyAdvice#determineWriteHints
• JsonViewRequestBodyAdvice and JsonViewResponseBodyAdvice supports both Jackson 2 (with wrappers) and Jackson 3 (with hints)
• org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter -> org.springframework.http.converter.AbstractJacksonHttpMessageConverter
• MappingJackson2HttpMessageConverter -> JacksonJsonHttpMessageConverter
• MappingJackson2SmileHttpMessageConverter -> JacksonSmileHttpMessageConverter
• MappingJackson2CborHttpMessageConverter -> JacksonCborHttpMessageConverter
• MappingJackson2XmlHttpMessageConverter -> JacksonXmlHttpMessageConverter
• MappingJackson2YamlHttpMessageConverter -> JacksonYamlHttpMessageConverter
• MappingJackson2JsonView -> JacksonJsonView
• MappingJackson2XmlView-> JacksonXmlView

WebFlux:

• org.springframework.http.codec.json.Jackson2CodecSupport -> org.springframework.http.codec.JacksonCodecSupport
• org.springframework.http.codec.json.Jackson2Tokenizer -> org.springframework.http.codec.JacksonTokenizer
• org.springframework.http.codec.json.Jackson2SmileDecoder -> org.springframework.http.codec.smile.JacksonSmileDecoder
• org.springframework.http.codec.json.Jackson2SmileEncoder -> org.springframework.http.codec.smile.JacksonSmileEncoder
• Jackson2CborDecoder -> JacksonCborDecoder
• Jackson2CborEncoder -> JacksonCborEncoder
• Jackson2JsonDecoder -> JacksonJsonDecoder
• Jackson2JsonEncoder -> JacksonJsonEncoder

Messaging:

• MappingJackson2MessageConverter -> JacksonJsonMessageConverter

JMS:

• MappingJackson2MessageConverter -> JacksonJsonMessageConverter

TODO:

• Fix RFC 9457 XML support via @JacksonXmlRootElement is ignored with Jackson 3 FasterXML/jackson-dataformat-xml#757
• Add support for hints in RestClient to support @JsonView and FilterProvider (no support in RestTemplate, migration path will be to switch to RestClient)
• Update the reference documentation

[sdeleuze]

See the related blog post https://cowtowncoder.medium.com/taking-jackson-3-0-0-rc1-for-a-spin-17282161a6b2.

[sdeleuze]

See FasterXML/jackson-future-ideas#83 (comment).