This commit adds new reference documentation sections about WebFlux
support in Spring Boot:
* Support for multiple HTTP servers (gh-8403)
* `CodecCustomizer` and JSON codecs (gh-8897, gh-9166)
* `WebClient.Builder` auto-configuration (gh-9522)
* Tests with `@WebFluxTest` (gh-8401)
* `WebTestClient` auto-configuration (gh-8399)
* Support for Thymeleafi and Mustache templating (gh-8124, gh-8648)
* Choose another HTTP server with WebFlux (closes gh-9690)
This commit applies what's been done in gh-9166 for WebFlux client and
server, but for the `WebTestClient` auto-configuration.
`WebTestClient` can be configured for mock or integration tests and this
change applies `CodecCustomizer` beans to the client being built.
Closes gh-9577
This commit introduces `CodecCustomizer`, a new callback-based interface
for customizing the codecs configuration for WebFlux server and client.
Instances of those customizers are applied to the `WebClient.Builder`
and to the `WebFluxAutoConfiguration` (which deals with both WebFlux and
WebFlux.fn).
For now, only Jackson codecs are auto-configured, by getting the
`ObjectMapper` instance created by Spring Boot. Other codecs can be
configured as soon as WebFlux supports those.
Closes gh-9166
This commit adds a new customizer interface for applying
configuration changes to `WebClient.Builder` beans:
`WebClientCustomizer`.
The new WebClient auto-configuration will make available, as a
prototype scoped bean, `WebClient.Builder` instances.
Once injected, developers can use those to create `WebClient`
instances to be used in their application.
`WebClientCustomizer` beans are sorted according to their
`Order` and then applied to the builder instances.
Closes gh-9522