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29.1.1 Spring MVC Auto-configuration

Spring Boot provides auto-configuration for Spring MVC that works well with most applications.

The auto-configuration adds the following features on top of Spring’s defaults:

• Inclusion of ContentNegotiatingViewResolver and BeanNameViewResolver beans.
  • 自动配置ViewResolver（视图解析器：根据方法的返回值获得视图对象(View)，视图对象决定如何渲染（转发？重定向？））
  • ContentNegotiatingViewResolver组合了所有的视图解析器
  • 如何定制？我们只需要给容器添加一个视图解析器，自动回将其组合进来
• Support for serving static resources, including support for WebJars (covered later in this document)).
• Automatic registration of Converter, GenericConverter, and Formatter beans.
  • Converter：转换器，比如public String test(User user);表单中传入的数字，true/false等都是文本，这些文本需要映射到User中，需要转换器，进行类型转换，将text(数字)-->int/integer，text(true)-->bool
  • Formatter ：格式化，2017/0/101--->Date
• Support for HttpMessageConverters (covered later in this document).
  • HttpMessageConverters：是SpringMVC用来http请求和响应的，比如将User--->json返回
  • HttpMessageConverters是从容器中确定的
• Automatic registration of MessageCodesResolver (covered later in this document).
• Static index.html support.
• Custom Favicon support (covered later in this document).
• Automatic use of a ConfigurableWebBindingInitializer bean (covered later in this document).

 

Spring Boot扩展 SpringMVC功能

在spring MVC中，我们可以编写xml来配置我们需要的一些功能，比如拦截器等等。

you can add your own @Configuration class of type WebMvcConfigurer but without @EnableWebMvc

我们可以在类型是WebMvcConfigurer的类上使用@Configuration注解，并且实现我们需要的方法；

@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor("拦截器对象").addPathPatterns("/hellow");
    }
}

 

Spring Boot全面接管SpringMVC功能

@EnableWebMvc
@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
    }
}

为什么加上@EnableWebMvc注解后spring mvc就是失效了呢？

1、导入DelegatingWebMvcConfiguration

@Import(DelegatingWebMvcConfiguration.class)
public @interface EnableWebMvc {
}

2、DelegatingWebMvcConfiguration 继承了 WebMvcConfigurationSupport 

@Configuration
public class DelegatingWebMvcConfiguration extends WebMvcConfigurationSupport {

3、查看 WebMvcAutoConfiguration 源码

@Configuration
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class })

//条件判断，组件中有没有WebMvcConfigurationSupport,没有才自动配置
@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
@AutoConfigureAfter({ DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class,
		ValidationAutoConfiguration.class })
public class WebMvcAutoConfiguration {

　

 

 

标签：SpringBoot,SpringMVC,Spring,视图,class,源码,covered,Configuration,public
来源： https://www.cnblogs.com/yanxiaoge/p/11357512.html