SpringBoot 2 WebMvcConfigurerAdapterの古い問題
WebMvcConfigurerの使用を推奨しますが、WebMvcConfigurationSupportでは問題があります.なぜWebMvcConfigurer.を使ったのかは明らかにされていません
WebMvcConfigurerAdapterソース注釈の説明を見てみましょう
/**
* An implementation of {@link WebMvcConfigurer} with empty methods allowing
* subclasses to override only the methods they're interested in.
*
* @author Rossen Stoyanchev
* @since 3.1
* @deprecated as of 5.0 {@link WebMvcConfigurer} has default methods (made
* possible by a Java 8 baseline) and can be implemented directly without the
* need for this adapter
*/
つまり、(Spirng)5.0からJava 8(インタフェースにデフォルトのdefaultメソッドがある)に基づいてインタフェースに直接書き込むため、アダプタを使用する必要はない.
WebMvcConfigurerのソースコードがWebMvcConfigurerインタフェースdefaultメソッドによって使用されているのを見てみましょう.確かにそうです.
/*
* Copyright 2002-2018 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
*
* http://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}.
*
* {@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:
*
* - RequestMappings
* - ViewControllerMappings
* - ResourcesMappings
*
* @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.
* Note 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.
*
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 resolvers) {
}
/**
* Add handlers to support custom controller method return value types.
*
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 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.
*
Note 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> 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> converters) {
}
/**
* Configure exception resolvers.
*
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.
*
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 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 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;
}
}