Apply codecs auto-configuration to webflux server and webclient

For Spring MVC, the HttpMessageConvertersAutoConfiguration configures the appropriate message converters for the server and the client (RestTemplate).

We should do the same for WebFlux, using ServerCodecConfigurer and ClientCodecConfigurer.

[alimate]

Probably the same issue

[bjornharvold]

Hi @bclozel

I did what I saw in the other ticket that started this and added:

@Bean
    Jackson2JsonEncoder jackson2JsonEncoder() {
        return new Jackson2JsonEncoder(objectMapper());
    }

    @Bean
    Jackson2JsonDecoder jackson2JsonDecoder() {
        return new Jackson2JsonDecoder(objectMapper());
    }

    @Bean
    WebFluxConfigurer webFluxConfigurer(Jackson2JsonEncoder encoder, Jackson2JsonDecoder decoder) {
        return new WebFluxConfigurer() {
            @Override
            public void configureHttpMessageCodecs(ServerCodecConfigurer configurer) {
                configurer.defaultCodecs().jackson2JsonEncoder(encoder);
                configurer.defaultCodecs().jackson2JsonDecoder(decoder);
            }
        };
    }

to my mock setup.