Java tutorial
/* * Copyright 2002-2019 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.web.servlet.config.annotation; import java.util.List; import org.springframework.core.convert.converter.Converter; import org.springframework.format.Formatter; import org.springframework.format.FormatterRegistry; import org.springframework.http.converter.HttpMessageConverter; import org.springframework.lang.Nullable; import org.springframework.validation.MessageCodesResolver; import org.springframework.validation.Validator; import org.springframework.web.method.support.HandlerMethodArgumentResolver; import org.springframework.web.method.support.HandlerMethodReturnValueHandler; import org.springframework.web.servlet.DispatcherServlet; import org.springframework.web.servlet.HandlerExceptionResolver; import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter; /** * Defines callback methods to customize the Java-based configuration for * Spring MVC enabled via {@code @EnableWebMvc}. * * <p>{@code @EnableWebMvc}-annotated configuration classes may implement * this interface to be called back and given a chance to customize the * default configuration. * * @author Rossen Stoyanchev * @author Keith Donald * @author David Syer * @since 3.1 */ 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 Converters} and {@link Formatter Formatters} 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 HttpMessageConverters} 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, org.springframework.web.accept.ContentNegotiationManager)}. * 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, org.springframework.web.accept.ContentNegotiationManager) */ 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, org.springframework.web.accept.ContentNegotiationManager) */ 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; } }