This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Framework 6.1.12! |
ResponseEntity
ResponseEntity
is like @ResponseBody
but with status and headers. For example:
-
Java
-
Kotlin
@GetMapping("/something")
public ResponseEntity<String> handle() {
String body = ... ;
String etag = ... ;
return ResponseEntity.ok().eTag(etag).body(body);
}
@GetMapping("/something")
fun handle(): ResponseEntity<String> {
val body = ...
val etag = ...
return ResponseEntity.ok().eTag(etag).build(body)
}
The body will usually be provided as a value object to be rendered to a corresponding
response representation (e.g. JSON) by one of the registered HttpMessageConverters
.
A ResponseEntity<Resource>
can be returned for file content, copying the InputStream
content of the provided resource to the response OutputStream
. Note that the
InputStream
should be lazily retrieved by the Resource
handle in order to reliably
close it after it has been copied to the response. If you are using InputStreamResource
for such a purpose, make sure to construct it with an on-demand InputStreamSource
(e.g. through a lambda expression that retrieves the actual InputStream
). Also, custom
subclasses of InputStreamResource
are only supported in combination with a custom
contentLength()
implementation which avoids consuming the stream for that purpose.
Spring MVC supports using a single value reactive type
to produce the ResponseEntity
asynchronously, and/or single and multi-value reactive
types for the body. This allows the following types of async responses:
-
ResponseEntity<Mono<T>>
orResponseEntity<Flux<T>>
make the response status and headers known immediately while the body is provided asynchronously at a later point. UseMono
if the body consists of 0..1 values orFlux
if it can produce multiple values. -
Mono<ResponseEntity<T>>
provides all three — response status, headers, and body, asynchronously at a later point. This allows the response status and headers to vary depending on the outcome of asynchronous request handling.