背景

在使用springcloud gateway启动过程中报错如下：

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 :: Spring Boot ::       (v2.1.12.RELEASE)

2021-04-26 10:21:35.671  INFO 11540 --- [           main] c.aimsphm.cloud.CloudGatewayApplication  : The following profiles are active: dev
2021-04-26 10:21:36.542  INFO 11540 --- [           main] o.s.cloud.context.scope.GenericScope     : BeanFactory id=a66473af-951b-3db6-9f82-a54be3b0c8a8
2021-04-26 10:21:36.659  INFO 11540 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.security.config.annotation.configuration.ObjectPostProcessorConfiguration' of type [org.springframework.security.config.annotation.configuration.ObjectPostProcessorConfiguration$$EnhancerBySpringCGLIB$$a670aa5d] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2021-04-26 10:21:36.669  INFO 11540 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'objectPostProcessor' of type [org.springframework.security.config.annotation.configuration.AutowireBeanFactoryObjectPostProcessor] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2021-04-26 10:21:36.673  INFO 11540 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.security.access.expression.method.DefaultMethodSecurityExpressionHandler@7e446d92' of type [org.springframework.security.access.expression.method.DefaultMethodSecurityExpressionHandler] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2021-04-26 10:21:36.678  INFO 11540 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.security.config.annotation.method.configuration.GlobalMethodSecurityConfiguration' of type [org.springframework.security.config.annotation.method.configuration.GlobalMethodSecurityConfiguration$$EnhancerBySpringCGLIB$$cb454d0f] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2021-04-26 10:21:36.682  INFO 11540 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.security.config.annotation.method.configuration.Jsr250MetadataSourceConfiguration' of type [org.springframework.security.config.annotation.method.configuration.Jsr250MetadataSourceConfiguration$$EnhancerBySpringCGLIB$$f09a6525] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2021-04-26 10:21:36.685  INFO 11540 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'jsr250MethodSecurityMetadataSource' of type [org.springframework.security.access.annotation.Jsr250MethodSecurityMetadataSource] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2021-04-26 10:21:36.686  INFO 11540 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'methodSecurityMetadataSource' of type [org.springframework.security.access.method.DelegatingMethodSecurityMetadataSource] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2021-04-26 10:21:36.699  INFO 11540 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration' of type [org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration$$EnhancerBySpringCGLIB$$29dce520] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2021-04-26 10:21:36.994  INFO 11540 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 10086 (http)
2021-04-26 10:21:37.018  INFO 11540 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-04-26 10:21:37.018  INFO 11540 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.30]
2021-04-26 10:21:37.149  INFO 11540 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-04-26 10:21:37.150  INFO 11540 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1466 ms
2021-04-26 10:21:37.510  INFO 11540 --- [           main] o.s.s.web.DefaultSecurityFilterChain     : Creating filter chain: any request, [org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter@34451ed8, org.springframework.security.web.context.SecurityContextPersistenceFilter@14168e1, org.springframework.security.web.header.HeaderWriterFilter@70029d2d, org.springframework.security.web.authentication.logout.LogoutFilter@4d157493, org.springframework.security.web.authentication.logout.LogoutFilter@71179b6f, org.springframework.security.cas.web.CasAuthenticationFilter@23da79eb, org.jasig.cas.client.session.SingleSignOutFilter@16a2ed51, org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter@6ecc02bb, org.springframework.security.web.savedrequest.RequestCacheAwareFilter@1e225820, org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter@6003ad65, org.springframework.security.web.authentication.AnonymousAuthenticationFilter@c1050f2, org.springframework.security.web.session.SessionManagementFilter@709f0202, org.springframework.security.web.access.ExceptionTranslationFilter@1e3ff233, org.springframework.security.web.access.intercept.FilterSecurityInterceptor@3cdc7b09]
2021-04-26 10:21:37.529  WARN 11540 --- [           main] c.n.c.sources.URLConfigurationSource     : No URLs will be polled as dynamic configuration sources.
2021-04-26 10:21:37.529  INFO 11540 --- [           main] c.n.c.sources.URLConfigurationSource     : To enable URLs as dynamic configuration sources, define System property archaius.configurationSource.additionalUrls or make config.properties available on classpath.
2021-04-26 10:21:37.534  WARN 11540 --- [           main] c.n.c.sources.URLConfigurationSource     : No URLs will be polled as dynamic configuration sources.
2021-04-26 10:21:37.534  INFO 11540 --- [           main] c.n.c.sources.URLConfigurationSource     : To enable URLs as dynamic configuration sources, define System property archaius.configurationSource.additionalUrls or make config.properties available on classpath.
2021-04-26 10:21:38.982  WARN 11540 --- [           main] GatewayClassPathWarningAutoConfiguration : 

**********************************************************

Spring MVC found on classpath, which is incompatible with Spring Cloud Gateway at this time. Please remove spring-boot-starter-web dependency.

**********************************************************


2021-04-26 10:21:41.034  WARN 11540 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'routeDefinitionRouteLocator' defined in class path resource [org/springframework/cloud/gateway/config/GatewayAutoConfiguration.class]: Unsatisfied dependency expressed through method 'routeDefinitionRouteLocator' parameter 1; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'modifyRequestBodyGatewayFilterFactory' defined in class path resource [org/springframework/cloud/gateway/config/GatewayAutoConfiguration.class]: Unsatisfied dependency expressed through method 'modifyRequestBodyGatewayFilterFactory' parameter 0; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.http.codec.ServerCodecConfigurer' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}
2021-04-26 10:21:41.038  INFO 11540 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2021-04-26 10:21:41.050  INFO 11540 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-04-26 10:21:41.176 ERROR 11540 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Parameter 0 of method modifyRequestBodyGatewayFilterFactory in org.springframework.cloud.gateway.config.GatewayAutoConfiguration required a bean of type 'org.springframework.http.codec.ServerCodecConfigurer' that could not be found.


Action:

Consider defining a bean of type 'org.springframework.http.codec.ServerCodecConfigurer' in your configuration.

看到错误实际上是有点懵的，但是智能的spring早已经告诉你可能需要的修改方式 

这是因为我的根pom引用spring-boot-starter-web导致的，需要取消掉。因为Spring Cloud Gateway 是使用 netty+webflux实现，webflux与web是冲突的。