@EnableWebMvc notes #EnableWebMvc

README.md

Springboot skips auto-configure the WebMvcAutoConfiguration, because it finds that there is org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration bean, and why did that bean instantiate because the user had @EnableWebMvc annotation on a @Configuration class. This is really screwed up.

WebMvcAutoConfiguration: Matched: - @ConditionalOnClass found required classes 'jakarta.servlet.Servlet', 'org.springframework.web.servlet.DispatcherServlet', 'org.springframework.web.servlet.config.annotation.WebMvcConfigurer' (OnClassCondition) - found 'session' scope (OnWebApplicationCondition) Did not match: - @ConditionalOnMissingBean (types: org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport; SearchStrategy: all) found beans of type 'org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport' org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration (OnBeanCondition)

When Springboot does configure the WebMvcAutoConfiguration, it will check the following conditions:

WebMvcAutoConfiguration matched: - @ConditionalOnClass found required classes 'jakarta.servlet.Servlet', 'org.springframework.web.servlet.DispatcherServlet', 'org.springframework.web.servlet.config.annotation.WebMvcConfigurer' (OnClassCondition) - found 'session' scope (OnWebApplicationCondition) - @ConditionalOnMissingBean (types: org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport; SearchStrategy: all) did not find any beans (OnBeanCondition)

three.java

	@Configuration
	@EnableWebMvc // Simply enables default MVC config from WebMvc and disables auto-configuration by WebMvcAutoConfiguration
	public static class OptIntoWebMvcMarkerConfiguration {
	}

	@Component
	@EnableWebMvc // Simply enables default MVC config from WebMvc and disables auto-configuration by WebMvcAutoConfiguration
	public static class ReplacingWebMvcConfigurer implements WebMvcConfigurer {
	}

	@Component

	// lack pf @EnableWebMvc allows WebMvcAutoConfiguration to do it's default thing and you can add to it
	// by implementing WebMvcConfigurer
	public static class AdditionalWebMvcConfigurer implements WebMvcConfigurer {
		@Override
		public void addResourceHandlers(ResourceHandlerRegistry registry) {
			WebMvcConfigurer.super.addResourceHandlers(registry);
			registry
					.addResourceHandler("/customization/**")
					.addResourceLocations("classpath:/customization/", "classpath:/static/");
		}
	}