Including Spring Data breaks auto serialization in Spring Boot application - spring

Question

I recently added Spring-data to my project and then I found that in my REST controllers, my models provided by clients were no longer being automatically serialized from JSON. How can I fix this?
I added:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>
and now the User param isn't having it's String arg constructor called and u is null!
#PostMapping()
#ResponseBody
public User createUser(HttpServletRequest request, #RequestParam("user") User u) {
log.info("Got user! " + u);
users.save(u);
Optional<User> found = users.findById(u.getEmail());
log.info("Saved user!! ");
return found.get();
}

Answer 1

If you build your .war with spring-data, run java -jar <path-to-war> --debug and then build it/run it without spring-data and diff the outputs, you can see that the following beans are included when spring-data is added.
SpringDataWebAutoConfiguration matched:
- #ConditionalOnClass found required classes 'org.springframework.data.web.PageableHandlerMethodArgumentResolver', 'org.springframework.web.servlet.config.annotation.WebMvcConfigurer' (OnClassCondition)
- found ConfigurableWebEnvironment (OnWebApplicationCondition)
- #ConditionalOnMissingBean (types: org.springframework.data.web.PageableHandlerMethodArgumentResolver; SearchStrategy: all) did not find any beans (OnBeanCondition)
SpringDataWebAutoConfiguration#pageableCustomizer matched:
- #ConditionalOnMissingBean (types: org.springframework.data.web.config.PageableHandlerMethodArgumentResolverCustomizer; SearchStrategy: all) did not find any beans (OnBeanCondition)
SpringDataWebAutoConfiguration#sortCustomizer matched:
- #ConditionalOnMissingBean (types: org.springframework.data.web.config.SortHandlerMethodArgumentResolverCustomizer; SearchStrategy: all) did not find any beans (OnBeanCondition)
This is because Spring data exposes REST controllers that link to your data repositories as mentioned here: http://spring.io/projects/spring-data-rest and this breaks the default auto-configurations for serializing objects passed to REST controllers.
Simply exclude the auto configuration and your existing auto serialization will work:
#SpringBootApplication(exclude = { SpringDataWebAutoConfiguration.class })
public class MyApplication{
public static void main(String[] args) {
SpringApplication.run(MyApplication.class, args);
}
}