Spring Cloud Gateway项目启动报错，报错信息如下：

2020-07-16 15:16:56.468 [main] ERROR o.s.boot.web.embedded.tomcat.TomcatStarter - Error starting Tomcat context. Exception: org.springframework.beans.factory.BeanCreationException. Message: Error creating bean with name 'servletEndpointRegistrar' defined in class path resource [org/springframework/boot/actuate/autoconfigure/endpoint/web/ServletEndpointManagementContextConfiguration$WebMvcServletEndpointManagementContextConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.boot.actuate.endpoint.web.ServletEndpointRegistrar]: Factory method 'servletEndpointRegistrar' threw exception; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'gatewayControllerEndpoint' defined in class path resource [org/springframework/cloud/gateway/config/GatewayAutoConfiguration$GatewayActuatorConfiguration.class]: Unsatisfied dependency expressed through method 'gatewayControllerEndpoint' parameter 2; 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: {}
2020-07-16 15:16:56.485 [main] INFO  org.apache.catalina.core.StandardService - Stopping service [Tomcat]
2020-07-16 15:16:56.490 [main] WARN  org.apache.catalina.loader.WebappClassLoaderBase - The web application [ROOT] appears to have started a thread named [spring.cloud.inetutils] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
 java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442)
 java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 java.lang.Thread.run(Thread.java:748)
2020-07-16 15:16:56.490 [main] WARN  org.apache.catalina.loader.WebappClassLoaderBase - The web application [ROOT] appears to have started a thread named [lettuce-eventExecutorLoop-1-1] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
 java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
 io.netty.util.concurrent.SingleThreadEventExecutor.takeTask(SingleThreadEventExecutor.java:251)
 io.netty.util.concurrent.DefaultEventExecutor.run(DefaultEventExecutor.java:64)
 io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:905)
 io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
 java.lang.Thread.run(Thread.java:748)
2020-07-16 15:16:56.492 [main] WARN  o.s.b.w.s.c.AnnotationConfigServletWebServerApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
2020-07-16 15:16:56.673 [main] ERROR o.s.b.diagnostics.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.

原因

Spring Cloud Gateway 基于WebFlux（底层是采用Reactive Netty的NIO框架）框架实现的，与传统的SpringMvc分属两大体系，所以之间存在依赖冲突，我们只需要把SpringMvc模块使用exclusion移除掉即可。

解决方式

<dependency> 
	<groupId>com.xxx.test</groupId>
	<artifactId>test-api</artifactId>
	<exclusions>
		<exclusion>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</exclusion>
	</exclusions>
</dependency>