need Spring Data JPA resource entry to make one many rest call - rest

Question

Using Spring Data jpa and Spring Data Rest I could able to get basic CRUD operations to work. But I am facing problem with one to many (owner -> car(s)) relationship. Can any one help me in this.
Owner.java
#Entity
#Table(name = "OWNER")
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class Owner implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#Column(name = "name")
private String name;
#Column(name = "age")
private Integer age;
#OneToMany(mappedBy = "owner")
#JsonIgnore
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
private Set<Car> cars = new HashSet<>();
}
OwnerResource.java
#RestController
#RequestMapping("/api")
public class OwnerResource {
private final Logger log = LoggerFactory.getLogger(OwnerResource.class);
#Inject
private OwnerRepository ownerRepository;
#RequestMapping(value = "/owners",
method = RequestMethod.POST,
produces = MediaType.APPLICATION_JSON_VALUE)
#Timed
public ResponseEntity<Owner> create(#RequestBody Owner owner) throws URISyntaxException {
log.debug("REST request to save Owner : {}", owner);
if (owner.getId() != null) {
return ResponseEntity.badRequest().header("Failure", "A new owner cannot already have an ID").body(null);
}
Owner result = ownerRepository.save(owner);
return ResponseEntity.created(new URI("/api/owners/" + result.getId()))
.headers(HeaderUtil.createEntityCreationAlert("owner", result.getId().toString()))
.body(result);
}
#RequestMapping(value = "/owners",
method = RequestMethod.PUT,
produces = MediaType.APPLICATION_JSON_VALUE)
#Timed
public ResponseEntity<Owner> update(#RequestBody Owner owner) throws URISyntaxException {
log.debug("REST request to update Owner : {}", owner);
if (owner.getId() == null) {
return create(owner);
}
Owner result = ownerRepository.save(owner);
return ResponseEntity.ok()
.headers(HeaderUtil.createEntityUpdateAlert("owner", owner.getId().toString()))
.body(result);
}
#RequestMapping(value = "/owners",
method = RequestMethod.GET,
produces = MediaType.APPLICATION_JSON_VALUE)
#Timed
public ResponseEntity<List<Owner>> getAll(#RequestParam(value = "page" , required = false) Integer offset,
#RequestParam(value = "per_page", required = false) Integer limit)
throws URISyntaxException {
Page<Owner> page = ownerRepository.findAll(PaginationUtil.generatePageRequest(offset, limit));
HttpHeaders headers = PaginationUtil.generatePaginationHttpHeaders(page, "/api/owners", offset, limit);
return new ResponseEntity<>(page.getContent(), headers, HttpStatus.OK);
}
#RequestMapping(value = "/owners/{id}",
method = RequestMethod.GET,
produces = MediaType.APPLICATION_JSON_VALUE)
#Timed
public ResponseEntity<Owner> get(#PathVariable Long id) {
log.debug("REST request to get Owner : {}", id);
return Optional.ofNullable(ownerRepository.findOne(id))
.map(owner -> new ResponseEntity<>(
owner,
HttpStatus.OK))
.orElse(new ResponseEntity<>(HttpStatus.NOT_FOUND));
}
}
OwnerRepository.java
/**
* Spring Data JPA repository for the Owner entity.
*/
public interface OwnerRepository extends JpaRepository<Owner,Long> {
}
The basic crud operation is working fine for Owner. But now I need to get all cars of a particular owner for that I need to add one rest call entry in OwnerResource.java and a method entry in OwneRepository.java. I tried different ways but getting many errors and is not working. The following is what I tried.
In OwnerRepository.java
Owner findAllByOwnerId(Long id);//But eclipse shows error here for this method
In OwnerResource.java
//Get All Cars
#RequestMapping(value = "/{id}/cars",
method = RequestMethod.GET,
produces = MediaType.APPLICATION_JSON_VALUE)
#Timed
public ResponseEntity<Owner> getAll(#PathVariable Long id) {
log.debug("REST request to get All Cars of the Owner : {}", id);
return Optional.ofNullable(ownerRepository.findAllByOwnerId(id))
.map(owner -> new ResponseEntity<>(
owner,
HttpStatus.OK))
.orElse(new ResponseEntity<>(HttpStatus.NOT_FOUND));
}
But these two changes are not working out. I am beginner to spring data jpa and spring data rest. Can any one help me in correcting these two so that I can get all cars of the owner.

Answer 1

I believe it shows an error because the findAll returns a different type of object: List, Page, etc...
Try this:
List<Owner> findAllByOwnerId(#Param("id") Long id);
That will return you a list of objects. If you want to return with pagination, than you need this instead:
Page<Owner> findAllByOwnerId(#Param("id") Long id, Pageable pageable);
I hope this helps, let me know how it works for you.