MockMvc ignores JsonFormat jackson annotation - spring-mvc

Question

I set-up a REST API with Spring MVC and Spring HATEOAS.
In one of the DTOs I put a JsonFormat on a ZonedDateTime field.
Running the server gives me the expected date format (yyyyMMdd), but with testing the annotation is ignored and I get something like 1454281200.000000000. So it looks like when testing the annotation is ignored totally. I tried the #JsonIgnore annotation, but that on was working.
No matter I use MockMvcBuilders.webAppContextSetup(wac).build() or MockMvcBuilders.standaloneSetup(membersController).build() the time is simply not converted to the JsonFormat as expected.
Anyone any idea's what going wrong here? I expect some configuration issue, but I don't know where to look at.
Discovered that the aDate on the Resource is serialised properly, but the xxxDTO.aDate is not serialised properly.
Resource
public class XxxResource extends Resource<XxxDTO> {
#JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyyMMdd")
private ZonedDateTime aDate;
public XxxResource(XxxDTO xxxDTO) {
super(xxxDTO);
this.aDate = xxxDTO.getADate();
}
}
DTO
public class XxxDTO {
#JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyyMMdd")
private ZonedDateTime aDate;
}
pom.xml
<jackson.version>2.8.3</jackson.version>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.3.3-RELEASE</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-jsr310</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.hateoas</groupId>
<artifactId>spring-hateoas</artifactId>
<version>0.20.0.RELEASE</version>
</dependency>
Test setup
#RunWith(MockitoJUnitRunner.class)
public class SomeTest {
XxxController xxxController = new XxxController(XxxService, new XxxResourceAssembler(),
new PagedResourcesAssembler<>(new HateoasPageableHandlerMethodArgumentResolver(), null));
this.mockMvc = MockMvcBuilders.standaloneSetup(xxxController).setCustomArgumentResolvers
(new PageableHandlerMethodArgumentResolver()).build();
}
The endpoints are set up through a web.xml and the WebMvcConfig is like this:
#Configuration
#EnableWebMvc
#EnableSpringDataWebSupport
public class WebMvcConfig extends WebMvcConfigurerAdapter {
#Override
public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
argumentResolvers.add(new PageableHandlerMethodArgumentResolver());
}
#Bean
public PagedResourcesAssembler pagedResourcesAssembler() {
return new PagedResourcesAssembler(new HateoasPageableHandlerMethodArgumentResolver(), null);
}
}