Spring Webflux : Webclient : Get body on error

I prefer to use the methods provided by the ClientResponse to handle http errors and throw exceptions:

WebClient.create()
         .post()
         .uri( url )
         .body( bodyObject == null ? null : BodyInserters.fromValue( bodyObject ) )
         .accept( MediaType.APPLICATION_JSON )
         .headers( headers )
         .exchange()
         .flatMap( clientResponse -> {
             //Error handling
             if ( clientResponse.statusCode().isError() ) { // or clientResponse.statusCode().value() >= 400
                 return clientResponse.createException().flatMap( Mono::error );
             }
             return clientResponse.bodyToMono( clazz )
         } )
         //You can do your checks: doOnError (..), onErrorReturn (..) ...
         ...

In fact, it’s the same logic used in the DefaultResponseSpec of DefaultWebClient to handle errors. The DefaultResponseSpec is an implementation of ResponseSpec that we would have if we made a retrieve() instead of exchange().