SpringBoot 2.0使用 WebMvcConfigurer 添加拦截器

问题：

    之前项目是springboot1.5版本的,后来想升级一下用2.0,但是在升级过后发现WebMvcConfigurerAdapter抽象类过时了

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@Deprecated
public abstract class WebMvcConfigurerAdapter implements WebMvcConfigurer {

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void configurePathMatch(PathMatchConfigurer configurer) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void addFormatters(FormatterRegistry registry) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void addCorsMappings(CorsRegistry registry) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> returnValueHandlers) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation is empty.
     */
    @Override
    public void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
    }

    /**
     * {@inheritDoc}
     * <p>This implementation returns {@code null}.
     */
    @Override
    @Nullable
    public Validator getValidator() {
        return null;
    }

    /**
     * {@inheritDoc}
     * <p>This implementation returns {@code null}.
     */
    @Override
    @Nullable
    public MessageCodesResolver getMessageCodesResolver() {
        return null;
    }

}

      WebMvcConfigurerAdapter是一个典型的适配器,这个抽象类中没有抽象方法,所有的方法都是对接口的一个空实现,这样的好处是用户类就只需要继承适配器类，只实现感兴趣的方法就行了。

springboot 2.0中这个抽象类已经过时,我们可以直接实现WebMvcConfigurer接口,2.0使用了java8的特性 default 方法。

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public interface WebMvcConfigurer {

    /**
     * Helps with configuring HandlerMappings path matching options such as trailing slash match,
     * suffix registration, path matcher and path helper.
     * Configured path matcher and path helper instances are shared for:
     * <ul>
     * <li>RequestMappings</li>
     * <li>ViewControllerMappings</li>
     * <li>ResourcesMappings</li>
     * </ul>
     * @since 4.0.3
     */
    default void configurePathMatch(PathMatchConfigurer configurer) {
    }

    /**
     * Configure content negotiation options.
     */
    default void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
    }

    /**
     * Configure asynchronous request handling options.
     */
    default void configureAsyncSupport(AsyncSupportConfigurer configurer) {
    }

    /**
     * Configure a handler to delegate unhandled requests by forwarding to the
     * Servlet container's "default" servlet. A common use case for this is when
     * the {@link DispatcherServlet} is mapped to "/" thus overriding the
     * Servlet container's default handling of static resources.
     */
    default void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
    }

    /**
     * Add {@link Converter}s and {@link Formatter}s in addition to the ones
     * registered by default.
     */
    default void addFormatters(FormatterRegistry registry) {
    }

    /**
     * Add Spring MVC lifecycle interceptors for pre- and post-processing of
     * controller method invocations. Interceptors can be registered to apply
     * to all requests or be limited to a subset of URL patterns.
     * <p><strong>Note</strong> that interceptors registered here only apply to
     * controllers and not to resource handler requests. To intercept requests for
     * static resources either declare a
     * {@link org.springframework.web.servlet.handler.MappedInterceptor MappedInterceptor}
     * bean or switch to advanced configuration mode by extending
     * {@link org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport
     * WebMvcConfigurationSupport} and then override {@code resourceHandlerMapping}.
     */
    default void addInterceptors(InterceptorRegistry registry) {
    }

    /**
     * Add handlers to serve static resources such as images, js, and, css
     * files from specific locations under web application root, the classpath,
     * and others.
     */
    default void addResourceHandlers(ResourceHandlerRegistry registry) {
    }

    /**
     * Configure cross origin requests processing.
     * @since 4.2
     */
    default void addCorsMappings(CorsRegistry registry) {
    }

    /**
     * Configure simple automated controllers pre-configured with the response
     * status code and/or a view to render the response body. This is useful in
     * cases where there is no need for custom controller logic -- e.g. render a
     * home page, perform simple site URL redirects, return a 404 status with
     * HTML content, a 204 with no content, and more.
     */
    default void addViewControllers(ViewControllerRegistry registry) {
    }

    /**
     * Configure view resolvers to translate String-based view names returned from
     * controllers into concrete {@link org.springframework.web.servlet.View}
     * implementations to perform rendering with.
     * @since 4.1
     */
    default void configureViewResolvers(ViewResolverRegistry registry) {
    }

    /**
     * Add resolvers to support custom controller method argument types.
     * <p>This does not override the built-in support for resolving handler
     * method arguments. To customize the built-in support for argument
     * resolution, configure {@link RequestMappingHandlerAdapter} directly.
     * @param resolvers initially an empty list
     */
    default void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
    }

    /**
     * Add handlers to support custom controller method return value types.
     * <p>Using this option does not override the built-in support for handling
     * return values. To customize the built-in support for handling return
     * values, configure RequestMappingHandlerAdapter directly.
     * @param handlers initially an empty list
     */
    default void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> handlers) {
    }

    /**
     * Configure the {@link HttpMessageConverter}s to use for reading or writing
     * to the body of the request or response. If no converters are added, a
     * default list of converters is registered.
     * <p><strong>Note</strong> that adding converters to the list, turns off
     * default converter registration. To simply add a converter without impacting
     * default registration, consider using the method
     * {@link #extendMessageConverters(java.util.List)} instead.
     * @param converters initially an empty list of converters
     */
    default void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
    }

    /**
     * A hook for extending or modifying the list of converters after it has been
     * configured. This may be useful for example to allow default converters to
     * be registered and then insert a custom converter through this method.
     * @param converters the list of configured converters to extend.
     * @since 4.1.3
     */
    default void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
    }

    /**
     * Configure exception resolvers.
     * <p>The given list starts out empty. If it is left empty, the framework
     * configures a default set of resolvers, see
     * {@link WebMvcConfigurationSupport#addDefaultHandlerExceptionResolvers(List)}.
     * Or if any exception resolvers are added to the list, then the application
     * effectively takes over and must provide, fully initialized, exception
     * resolvers.
     * <p>Alternatively you can use
     * {@link #extendHandlerExceptionResolvers(List)} which allows you to extend
     * or modify the list of exception resolvers configured by default.
     * @param resolvers initially an empty list
     * @see #extendHandlerExceptionResolvers(List)
     * @see WebMvcConfigurationSupport#addDefaultHandlerExceptionResolvers(List)
     */
    default void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
    }

    /**
     * Extending or modify the list of exception resolvers configured by default.
     * This can be useful for inserting a custom exception resolver without
     * interfering with default ones.
     * @param resolvers the list of configured resolvers to extend
     * @since 4.3
     * @see WebMvcConfigurationSupport#addDefaultHandlerExceptionResolvers(List)
     */
    default void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
    }

    /**
     * Provide a custom {@link Validator} instead of the one created by default.
     * The default implementation, assuming JSR-303 is on the classpath, is:
     * {@link org.springframework.validation.beanvalidation.OptionalValidatorFactoryBean}.
     * Leave the return value as {@code null} to keep the default.
     */
    @Nullable
    default Validator getValidator() {
        return null;
    }

    /**
     * Provide a custom {@link MessageCodesResolver} for building message codes
     * from data binding and validation error codes. Leave the return value as
     * {@code null} to keep the default.
     */
    @Nullable
    default MessageCodesResolver getMessageCodesResolver() {
        return null;
    }

}

      2.0 中也可以使用WebMvcConfigurationSupport但这样会使自动配置失效,需要重新配置后才可以有效

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@Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {

        registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/");

        super.addResourceHandlers(registry);
}

      综上2.0中实现WebMvcConfigure接口,配置拦截器是最合适的