Difference between WebMvcConfigurationSupport and WebMvcConfigurerAdapter

Question

I would like to add resource handlers. In the forum they use WebMvcConfigurationSupport: http://forum.springsource.org/showthread.php?116068-How-to-configure-lt

Answer 1

I was recently solving this very same problem when configuring converters and it resulted in quite a long post.

By default Spring Boot uses its implementation of WebMvcConfigurationSupport and does a lot of auto-magic including finding all the WebMvcConfigurer and using them. There is one implementation provided by Boot already and you may add more. This results in seemingly confusing behaviour when the list of converters coming to configureMessageConverters in your implementation of WebMvcConfigurer is already pre-populated from previous configurer.

These types (WebMvcConfigurationSupport and WebMvcConfigurer) have also strikingly similar interface - but the first does NOT implement the other. The point is:

Support class searches for configurers and uses them + does something on its own.

If you extend from WebMvcConfigurationSupport you take over the configuration and while there are some things available that are not in WebMvcConfigurer (like addDefaultHttpMessageConverters) there is also tons of code from EnableWebMvcConfiguration and DelegatingWebMvcConfiguration that does not happen.

Both extending WebMvcConfigurationSupport or WebMvcConfigurer (not sure both at once makes much sense) have their valid usages, but with extending the support class you take over the process much more and lose a lot of "opinionated" Spring Boot functionality.