i face a problem when i using spring cloud gateway
is if any dependency call spring-boot-starter-tomcat directly or recursively
it will not work because it will start the embedded tomcat server not the netty server that spring cloud gateway use
i started to solve this problem by excluding this dependency
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
the spring cloud gateway worked successfully
but sometimes i want to use spring-cloud-starter-oauth2 to use @EnableOAuth2Sso
i start to use
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-oauth2</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
at that time i face the big issue that throw exception saying
Caused by: java.lang.IllegalStateException: Failed to introspect annotated methods on class org.springframework.security.oauth2.config.annotation.web.configuration.OAuth2ClientConfiguration ......
Caused by: java.lang.NoClassDefFoundError: javax/servlet/Filter