SpringBoot---初探MVC自动配置原理 (3)

回到WebMvcAutoConfiguration类

@Configuration(proxyBeanMethods = false) @ConditionalOnWebApplication(type = Type.SERVLET) @ConditionalOnClass({ Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class }) @ConditionalOnMissingBean(WebMvcConfigurationSupport.class) @AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10) @AutoConfigureAfter({ DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class, ValidationAutoConfiguration.class }) public class WebMvcAutoConfiguration {}

注意看第四行--->@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)

这是一个条件判断，没有WebMvcConfigurationSupport类才能让本类生效

一旦使用@EnableWebMvc，就会使其生效，从而让SpringBoot有关webMVC的自动配置失效