一、简介

WebMvcConfigurer配置类其实是Spring内部的一种配置方式，采用JavaBean的形式来代替传统的xml配置文件形式进行针对框架个性化定制，可以自定义一些Handler，Interceptor，ViewResolver，MessageConverter。基于java-based方式的spring mvc配置，需要创建一个配置类并实现WebMvcConfigurer 接口；

在Spring Boot 1.5版本都是靠重写WebMvcConfigurerAdapter的方法来添加自定义拦截器，消息转换器等。SpringBoot 2.0 后，该类被标记为@Deprecated（弃用）。官方推荐直接实现WebMvcConfigurer或者直接继承WebMvcConfigurationSupport，方式一实现WebMvcConfigurer接口（推荐），方式二继承WebMvcConfigurationSupport类

二、接口

public interface WebMvcConfigurer {void configurePathMatch(PathMatchConfigurer var1);void configureContentNegotiation(ContentNegotiationConfigurer var1);void configureAsyncSupport(AsyncSupportConfigurer var1);void configureDefaultServletHandling(DefaultServletHandlerConfigurer var1);void addFormatters(FormatterRegistry var1);void addInterceptors(InterceptorRegistry var1);void addResourceHandlers(ResourceHandlerRegistry var1);void addCorsMappings(CorsRegistry var1);void addViewControllers(ViewControllerRegistry var1);void configureViewResolvers(ViewResolverRegistry var1);void addArgumentResolvers(List<HandlerMethodArgumentResolver> var1);void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> var1);void configureMessageConverters(List<HttpMessageConverter<?>> var1);void extendMessageConverters(List<HttpMessageConverter<?>> var1);void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> var1);void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> var1);Validator getValidator();MessageCodesResolver getMessageCodesResolver();
}

其中，常用的是

 /* 拦截器配置 */
void addInterceptors(InterceptorRegistry var1);
/* 视图跳转控制器 */
void addViewControllers(ViewControllerRegistry registry);
/***静态资源处理
**/
void addResourceHandlers(ResourceHandlerRegistry registry);
/* 默认静态资源处理器 */
void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer);
/*** 这里配置视图解析器**/
void configureViewResolvers(ViewResolverRegistry registry);
/* 配置内容裁决的一些选项*/
void configureContentNegotiation(ContentNegotiationConfigurer configurer);
/** 解决跨域问题 **/
public void addCorsMappings(CorsRegistry registry) ;

1、addInterceptors拦截器

• addInterceptor：需要一个实现HandlerInterceptor接口的拦截器实例
• addPathPatterns：用于设置拦截器的过滤路径规则；addPathPatterns("/**")对所有请求都拦截
• excludePathPatterns：用于设置不需要拦截的过滤规则

@Override
public void addInterceptors(InterceptorRegistry registry) {super.addInterceptors(registry);registry.addInterceptor(new TestInterceptor()).addPathPatterns("/**").excludePathPatterns("/emp/toLogin","/emp/login","/js/**","/css/**","/images/**");
}

 2、addCorsMappings跨域

@Override
public void addCorsMappings(CorsRegistry registry) {super.addCorsMappings(registry);registry.addMapping("/cors/**").allowedHeaders("*").allowedMethods("POST","GET").allowedOrigins("*");
}