SpringBoot笔记整理（四）

SpringBoot笔记整理（一）
SpringBoot笔记整理（二）
SpringBoot笔记整理（三）
SpringBoot笔记整理（四）

1、SpringMVC自动配置

以下是SpringBoot对SpringMVC

• nclusion of ContentNegotiatingViewResolver and BeanNameViewResolver beans.
  自动配置了ViewResolver

• Support for serving static resources, including support for WebJars .

• registration of Converter, GenericConverter, and Formatter beans.

• Support for HttpMessageConverters .

• Automatic registration of MessageCodesResolver .

• Static index.html support.

• Custom Favicon support .

• Automatic use of a ConfigurableWebindingInitializer bean .

If you want to keep Spring Boot MVC features and you want to add additional MVC configuration (interceptors, formatters, view controllers, and other features), you can add your own class of type WebMvcConfigurerAdapter but without @EnableWebMvc. If you wish to provide custom instances of RequestMappingHandlerMapping,RequestMappingHandlerAdapter, or ExceptionHandExceptionResolver, you can declare a WebMvcRegistrationsAdapter instance to provide such components.
If you want to take complete control of Spring MVC, you can add your own @Configuration annotated with @EnableWebMvc.

2、扩展SpringMVC

<mvc:view-controller path="/hello" view-name="success"/>
<mvc:interceptors>
    <mvc:interceptor>
        <mvc:mapping path="/hello"/>
        <bean></bean>
    </mvc:interceptor>
</mvc:interceptors>

编写一个配置类（@Configuration），是WebMvcConfigurationAdapter类型；不能标注@EnableWebMvc

既保留了所有的自动配置，也能用我们扩展的配置

//使用WebMvcConfigurer可以来扩展SpringMVC的功能
@Configuration
public class MyMvcConfig implements WebMvcConfigurer {

    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        //浏览器发送/athomyit请求来到 success
        registry.addViewController("/athomyit").setViewName("success");
    }
}

原理：
1）WebMvcAutoConfiguration是SpringMVC的自动配置类。
2）在做其他自动配置时会导入：@Import（EnableWebMvcConfiguration.class）

@Configuration(
    proxyBeanMethods = false
)
public static class EnableWebMvcConfiguration extends DelegatingWebMvcConfiguration implements ResourceLoaderAware {
    
    
    //从容器中获取所有的WebMVCConfigurer
    @Autowired(
    required = false
)
public void setConfigurers(List<WebMvcConfigurer> configurers) {
    if (!CollectionUtils.isEmpty(configurers)) {
        this.configurers.addWebMvcConfigurers(configurers);
    }

}

3）容器中所有的WebMvcConfigurer都会一起起作用

4）我们的配置类也会被调用
效果：SpringMVC的自动配置和我们的拓展配置都会起作用

3、全面接管SpringMVC

SpringBoot对SpringMVC的自动配置不需要了，所有的都是我们自己配置，所有的SpringMVC的自动配置都失效了

我们需要在配置类中添加@EnableWebMvc即可

//使用WebMvcConfigurerAdapter可以来扩展SpringMVC的功能
@EnableWebMvc
@Configuration
public class MyMvcConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
       // super.addViewControllers(registry);
        //浏览器发送 /atguigu 请求来到 success
        registry.addViewController("/atguigu").setViewName("success");
    }
}