ResponseEntity represents the whole HTTP response: status code, headers, and body. As a result, we can use it to fully configure the HTTP response.
ResponseEntity represents an HTTP response, including headers, body, and status. While @ResponseBody puts the return value into the body of the response, ResponseEntity also allows us to add headers and status code.
Your controller method should only return ResponseEntity<Success> . It will not be responsible for returning error or exception responses. You will implement a class that handles exceptions for all controllers.
NOTE: This is true for the version mentioned in the question, 4.1.1.RELEASE.
Spring MVC handles a ResponseEntity
return value through HttpEntityMethodProcessor
.
When the ResponseEntity
value doesn't have a body set, as is the case in your snippet, HttpEntityMethodProcessor
tries to determine a content type for the response body from the parameterization of the ResponseEntity
return type in the signature of the @RequestMapping
handler method.
So for
public ResponseEntity<Void> taxonomyPackageExists( @PathVariable final String key ) {
that type will be Void
. HttpEntityMethodProcessor
will then loop through all its registered HttpMessageConverter
instances and find one that can write a body for a Void
type. Depending on your configuration, it may or may not find any.
If it does find any, it still needs to make sure that the corresponding body will be written with a Content-Type that matches the type(s) provided in the request's Accept
header, application/xml
in your case.
If after all these checks, no such HttpMessageConverter
exists, Spring MVC will decide that it cannot produce an acceptable response and therefore return a 406 Not Acceptable HTTP response.
With ResponseEntity<String>
, Spring will use String
as the response body and find StringHttpMessageConverter
as a handler. And since StringHttpMessageHandler
can produce content for any media type (provided in the Accept
header), it will be able to handle the application/xml
that your client is requesting.
Spring MVC has since been changed to only return 406 if the body in the ResponseEntity
is NOT null
. You won't see the behavior in the original question if you're using a more recent version of Spring MVC.
In iddy85's solution, which seems to suggest ResponseEntity<?>
, the type for the body will be inferred as Object
. If you have the correct libraries in your classpath, ie. Jackson (version > 2.5.0) and its XML extension, Spring MVC will have access to MappingJackson2XmlHttpMessageConverter
which it can use to produce application/xml
for the type Object
. Their solution only works under these conditions. Otherwise, it will fail for the same reason I've described above.
According Spring 4 MVC ResponseEntity.BodyBuilder and ResponseEntity Enhancements Example it could be written as:
....
return ResponseEntity.ok().build();
....
return ResponseEntity.noContent().build();
UPDATE:
If returned value is Optional
, there are convinient method, returned ok()
or notFound()
:
return ResponseEntity.of(optional)
You can also not specify the type parameter which seems a bit cleaner and what Spring intended when looking at the docs:
@RequestMapping(method = RequestMethod.HEAD, value = Constants.KEY )
public ResponseEntity taxonomyPackageExists( @PathVariable final String key ){
// ...
return new ResponseEntity(HttpStatus.NO_CONTENT);
}
Your method implementation is ambiguous, try the following , edited your code a little bit and used HttpStatus.NO_CONTENT
i.e 204 No Content as in place of HttpStatus.OK
The server has fulfilled the request but does not need to return an entity-body, and might want to return updated metainformation. The response MAY include new or updated metainformation in the form of entity-headers, which if present SHOULD be associated with the requested variant.
Any value of T will be ignored for 204, but not for 404
public ResponseEntity<?> taxonomyPackageExists( @PathVariable final String key ) {
LOG.debug( "taxonomyPackageExists queried with key: {0}", key ); //$NON-NLS-1$
final TaxonomyKey taxonomyKey = TaxonomyKey.fromString( key );
LOG.debug( "Taxonomy key created: {0}", taxonomyKey ); //$NON-NLS-1$
if ( this.xbrlInstanceValidator.taxonomyPackageExists( taxonomyKey ) ) {
LOG.debug( "Taxonomy package with key: {0} exists.", taxonomyKey ); //$NON-NLS-1$
return new ResponseEntity<T>(HttpStatus.NO_CONTENT);
} else {
LOG.debug( "Taxonomy package with key: {0} does NOT exist.", taxonomyKey ); //$NON-NLS-1$
return new ResponseEntity<T>( HttpStatus.NOT_FOUND );
}
}
For Spring 5.2+ this works for me:
@PostMapping("/foo")
ResponseEntity<Void> foo(@PathVariable UUID fooId) {
return fooService.findExam(fooId)
.map(uri -> ResponseEntity.noContent().<Void>build())
.orElse(ResponseEntity.notFound().build());
}
Personally, to deal with empty responses, I use in my Integration Tests the MockMvcResponse object like this :
MockMvcResponse response = RestAssuredMockMvc.given()
.webAppContextSetup(webApplicationContext)
.when()
.get("/v1/ticket");
assertThat(response.mockHttpServletResponse().getStatus()).isEqualTo(HttpStatus.NO_CONTENT.value());
and in my controller I return empty response in a specific case like this :
return ResponseEntity.noContent().build();
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