@ConfigurationProperties(prefix = "spring.resources", ignoreUnknownFields = false)
public class ResourceProperties implements ResourceLoaderAware {
  //可以设置和静态资源有关的参数，缓存时间等

WebMvcAuotConfiguration：
	@Override
	public void addResourceHandlers(ResourceHandlerRegistry registry) {
		if (!this.resourceProperties.isAddMappings()) {
			logger.debug("Default resource handling disabled");
			return;
		}
		Integer cachePeriod = this.resourceProperties.getCachePeriod();
		if (!registry.hasMappingForPattern("/webjars/**")) {
			customizeResourceHandlerRegistration(
					registry.addResourceHandler("/webjars/**")
							.addResourceLocations(
									"classpath:/META-INF/resources/webjars/")
					.setCachePeriod(cachePeriod));
		}
		String staticPathPattern = this.mvcProperties.getStaticPathPattern();
         	//静态资源文件夹映射
		if (!registry.hasMappingForPattern(staticPathPattern)) {
			customizeResourceHandlerRegistration(
					registry.addResourceHandler(staticPathPattern)
							.addResourceLocations(
									this.resourceProperties.getStaticLocations())
					.setCachePeriod(cachePeriod));
		}
	}

       //配置欢迎页映射
	@Bean
	public WelcomePageHandlerMapping welcomePageHandlerMapping(
			ResourceProperties resourceProperties) {
		return new WelcomePageHandlerMapping(resourceProperties.getWelcomePage(),
				this.mvcProperties.getStaticPathPattern());
	}

      //配置喜欢的图标
	@Configuration
	@ConditionalOnProperty(value = "spring.mvc.favicon.enabled", matchIfMissing = true)
	public static class FaviconConfiguration {

		private final ResourceProperties resourceProperties;

		public FaviconConfiguration(ResourceProperties resourceProperties) {
			this.resourceProperties = resourceProperties;
		}

		@Bean
		public SimpleUrlHandlerMapping faviconHandlerMapping() {
			SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping();
			mapping.setOrder(Ordered.HIGHEST_PRECEDENCE + 1);
             	//所有  **/favicon.ico 
			mapping.setUrlMap(Collections.singletonMap("**/favicon.ico",
					faviconRequestHandler()));
			return mapping;
		}

		@Bean
		public ResourceHttpRequestHandler faviconRequestHandler() {
			ResourceHttpRequestHandler requestHandler = new ResourceHttpRequestHandler();
			requestHandler
					.setLocations(this.resourceProperties.getFaviconLocations());
			return requestHandler;
		}

	}

@ConfigurationProperties(prefix = "spring.thymeleaf")
public class ThymeleafProperties {

	private static final Charset DEFAULT_ENCODING = Charset.forName("UTF-8");

	private static final MimeType DEFAULT_CONTENT_TYPE = MimeType.valueOf("text/html");

	public static final String DEFAULT_PREFIX = "classpath:/templates/";

	public static final String DEFAULT_SUFFIX = ".html";
  	//

@Bean
@ConditionalOnProperty(prefix = "spring.mvc", name = "date-format")//在文件中配置日期格式化的规则
public Formatter<Date> dateFormatter() {
	return new DateFormatter(this.mvcProperties.getDateFormat());//日期格式化组件
}

//使用WebMvcConfigurerAdapter可以来扩展SpringMVC的功能
@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");
    }
}

   @Configuration
public static class EnableWebMvcConfiguration extends DelegatingWebMvcConfiguration {
     private final WebMvcConfigurerComposite configurers = new WebMvcConfigurerComposite();

 //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);
           	//一个参考实现；将所有的WebMvcConfigurer相关配置都来一起调用；  
           	@Override
            // public void addViewControllers(ViewControllerRegistry registry) {
             //    for (WebMvcConfigurer delegate : this.delegates) {
              //       delegate.addViewControllers(registry);
              //   }
             }
         }
}

//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");
    }
}

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

@Configuration
public class DelegatingWebMvcConfiguration extends WebMvcConfigurationSupport {

@Configuration
@ConditionalOnWebApplication
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class,
		WebMvcConfigurerAdapter.class })
//容器中没有这个组件的时候，这个自动配置类才生效
@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
@AutoConfigureAfter({ DispatcherServletAutoConfiguration.class,
		ValidationAutoConfiguration.class })
public class WebMvcAutoConfiguration {

//使用WebMvcConfigurerAdapter可以来扩展SpringMVC的功能
//@EnableWebMvc   不要接管SpringMVC
@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");
    }

    //所有的WebMvcConfigurerAdapter组件都会一起起作用
    @Bean //将组件注册在容器
    public WebMvcConfigurerAdapter webMvcConfigurerAdapter(){
        WebMvcConfigurerAdapter adapter = new WebMvcConfigurerAdapter() {
            @Override
            public void addViewControllers(ViewControllerRegistry registry) {
                registry.addViewController("/").setViewName("login");
                registry.addViewController("/index.html").setViewName("login");
            }
        };
        return adapter;
    }
}

@ConfigurationProperties(prefix = "spring.messages")
public class MessageSourceAutoConfiguration {
    
    /**
	 * Comma-separated list of basenames (essentially a fully-qualified classpath
	 * location), each following the ResourceBundle convention with relaxed support for
	 * slash based locations. If it doesn't contain a package qualifier (such as
	 * "org.mypackage"), it will be resolved from the classpath root.
	 */
	private String basename = "messages";  
    //我们的配置文件可以直接放在类路径下叫messages.properties；
    
    @Bean
	public MessageSource messageSource() {
		ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
		if (StringUtils.hasText(this.basename)) {
            //设置国际化资源文件的基础名（去掉语言国家代码的）
			messageSource.setBasenames(StringUtils.commaDelimitedListToStringArray(
					StringUtils.trimAllWhitespace(this.basename)));
		}
		if (this.encoding != null) {
			messageSource.setDefaultEncoding(this.encoding.name());
		}
		messageSource.setFallbackToSystemLocale(this.fallbackToSystemLocale);
		messageSource.setCacheSeconds(this.cacheSeconds);
		messageSource.setAlwaysUseMessageFormat(this.alwaysUseMessageFormat);
		return messageSource;
	}

		@Bean
		@ConditionalOnMissingBean
		@ConditionalOnProperty(prefix = "spring.mvc", name = "locale")
		public LocaleResolver localeResolver() {
			if (this.mvcProperties
					.getLocaleResolver() == WebMvcProperties.LocaleResolver.FIXED) {
				return new FixedLocaleResolver(this.mvcProperties.getLocale());
			}
			AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
			localeResolver.setDefaultLocale(this.mvcProperties.getLocale());
			return localeResolver;
		}
默认的就是根据请求头带来的区域信息获取Locale进行国际化

/**
 * 可以在连接上携带区域信息
 */
public class MyLocaleResolver implements LocaleResolver {
    
    @Override
    public Locale resolveLocale(HttpServletRequest request) {
        String l = request.getParameter("l");
        Locale locale = Locale.getDefault();
        if(!StringUtils.isEmpty(l)){
            String[] split = l.split("_");
            locale = new Locale(split[0],split[1]);
        }
        return locale;
    }

    @Override
    public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) {

    }
}


 @Bean
    public LocaleResolver localeResolver(){
        return new MyLocaleResolver();
    }
}

/**
 * 登陆检查，
 */
public class LoginHandlerInterceptor implements HandlerInterceptor {
    //目标方法执行之前
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        Object user = request.getSession().getAttribute("loginUser");
        if(user == null){
            //未登陆，返回登陆页面
            request.setAttribute("msg","没有权限请先登陆");
            request.getRequestDispatcher("/index.html").forward(request,response);
            return false;
        }else{
            //已登陆，放行请求
            return true;
        }

    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}

//所有的WebMvcConfigurerAdapter组件都会一起起作用
  @Bean //将组件注册在容器
  public WebMvcConfigurerAdapter webMvcConfigurerAdapter(){
      WebMvcConfigurerAdapter adapter = new WebMvcConfigurerAdapter() {
          @Override
          public void addViewControllers(ViewControllerRegistry registry) {
              registry.addViewController("/").setViewName("login");
              registry.addViewController("/index.html").setViewName("login");
              registry.addViewController("/main.html").setViewName("dashboard");
          }

          //注册拦截器
          @Override
          public void addInterceptors(InterceptorRegistry registry) {
              //super.addInterceptors(registry);
              //静态资源；  *.css , *.js
              //SpringBoot已经做好了静态资源映射
              registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**")
                      .excludePathPatterns("/index.html","/","/user/login");
          }
      };
      return adapter;
  }