I have a controller annotated with @RestController
and it implements an interface:
public interface ContratEndpoint {
String ROOT = "/api/contrats";
String GET_CONTRAT = "";
String GET_CONTRAT_PER_PK = "/{idContrat}";
@RequestMapping(value = GET_CONTRAT)
Contrat getContrat(@RequestParam(value = "contratId")Long contratId);
@RequestMapping(value = GET_CONTRAT_PER_ID)
ExtContrat getContratById(@PathVariable("idContrat") Long idContrat);
}
The controller:
@RestController
@RequestMapping(value = ContratEndpoint.ROOT)
public class ContratController implements ContratEndpoint {
//Injecting Services....
@Resource
private Mapper mapper;
@Override
public Contrat getContrat(Long contratId) {
return mapper.map(contratService.get(contratId),Contrat.class);
}
@Override
public ExtContrat getContratById(@PathVariable("idContrat") Long idContrat){
Preconditions.checkArgument(idContrat !=null);
return mapper.map(contratService.get(idContrat),ExtContrat.class);
}
.The above Code works just fine.
. But For the first inherited method , I didn't have to annotate arguments with @RequestParam
and it worked just fine.
As for the second method I tried at first :
@Override
public ExtContrat getContratById(Long idContrat){
Preconditions.checkArgument(idContrat !=null);
return mapper.map(contratService.get(idContrat),ExtContrat.class);
}
. I expected the same behaviour Like the first Method, But i was wrong and the code ended up firing an IllegalArgumentException
because of the check in ligne Preconditions.checkArgument(idContrat!=null)
.
My question is what is so specific about @PathVariable
that i've missed ?
Or is it just something is wrong with my approach?
Thanks.
There is difference between Request param and path variable,seee below post that you can confirm with your uri the cause for the exception :
@PathVariable is to obtain some placeholder from the uri (Spring call it an URI Template) — see Spring Reference Chapter 16.3.2.2 URI Template Patterns
@RequestParam is to obtain an parameter — see Spring Reference Chapter 16.3.3.3 Binding request parameters to method parameters with @RequestParam
Assume this Url http://localhost:8080/SomeApp/user/1234/invoices?date=12-05-2013 (to get the invoices for user 1234 for today)
@RequestMapping(value="/user/{userId}/invoices", method = RequestMethod.GET)
public List<Invoice> listUsersInvoices(
@PathVariable("userId") int user,
@RequestParam(value = "date", required = false) Date dateOrNull) {
...
}