I am using spring-data-rest to expose entities as (paged) rest resources. Everything works fine, but when I request data via RestTemplate
, I get an useless HATEOAS JSON (which I didn't ask for). The JSON seems to be a PagedResources. I could live with that, but the JSON isn't converted into an object correctly. There is no content
inside.
Repository:
@RepositoryRestResource(collectionResourceRel = "people", path = "people")
public interface PersonRepository extends PagingAndSortingRepository<Person, Long>
{
List<Person> findByLastName(@Param("name") String name);
}
Client:
public List<Person> getPersons()
{
RestTemplate rt = new RestTemplate();
System.out.println(rt.getForObject(URL, PagedResources.class).getContent().size());
System.out.println(rt.getForObject(URL, PagedResources.class).getLinks().size());
System.out.println(rt.getForObject(URL, PagedResources.class).getMetadata().getTotalElements());
return new ArrayList<Person>(rt.getForObject(URL, PagedResources.class).getContent()); // <-- empty
}
System.out:
0 // getContent().size()
4 // getLinks().size()
2 // getTotalElements()
curl:
C:\...>curl http://localhost:8080/spring-jsf-rest/rest/people
{
"_links" : {
"self" : {
"href" : "http://localhost:8080/spring-jsf-rest/rest/people{?page,size,sort}",
"templated" : true
},
"search" : {
"href" : "http://localhost:8080/spring-jsf-rest/rest/people/search"
}
},
"_embedded" : {
"people" : [ {
"firstName" : "John",
"lastName" : "Rambo",
"_links" : {
"self" : {
"href" : "http://localhost:8080/spring-jsf-rest/rest/people/1"
}
}
}, {
"firstName" : "Chuck",
"lastName" : "Norris",
"_links" : {
"self" : {
"href" : "http://localhost:8080/spring-jsf-rest/rest/people/2"
}
}
} ]
},
"page" : {
"size" : 20,
"totalElements" : 2,
"totalPages" : 1,
"number" : 0
}
}
It seems like _embedded
is not mapped correctly to content?!
As you've discovered correctly, PagedResources
does not have an _embedded
property, that's why you don't get the content
property populated.
This dilemma can be solved in two different ways:
Providing a type that matches the representation in the first place. Thus, craft a custom class and either stick to the property names of the representation or customize it using Jackson annotations etc.
Set up a custom MappingJackson2HttpMessageConverter
and customize the ObjectMapper
to get the Jackson2HalModule
configured that Spring HATEOAS ships out of the box.
ObjectMapper mapper = new ObjectMapper();
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
mapper.registerModule(new Jackson2HalModule());
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
converter.setSupportedMediaTypes(MediaType.parseMediaTypes("application/hal+json"));
converter.setObjectMapper(mapper);
RestTemplate template = new RestTemplate(Collections.<HttpMessageConverter<?>> singletonList(converter));