Spring Tomcat dependencies exception Loading in Gradle

Question

I am using Spring Boot with Jetty, and it seems like I cannot exclude all Tomcat dependencies in the Gradle build file.

Relevant part of build.gradle:

compile("org.springframework.boot:spring-boot-starter") {
    exclude module: "tomcat-embed-el"
}
compile("org.springframework.boot:spring-boot-starter-jetty")

compile("org.springframework.boot:spring-boot-starter-web") {
    exclude module: "spring-boot-starter-tomcat"
}

However, when I run gradle dependenciesthe tomcat parts still exist and cause problems with WebSockets:

...
|    
+--- org.springframework.boot:spring-boot-starter-web: -> 1.4.1.RELEASE
|    +--- org.springframework.boot:spring-boot-starter:1.4.1.RELEASE (*)
|    +--- org.hibernate:hibernate-validator:5.2.4.Final
|    |    +--- javax.validation:validation-api:1.1.0.Final
|    |    +--- org.jboss.logging:jboss-logging:3.2.1.Final -> 3.3.0.Final
|    |    \--- com.fasterxml:classmate:1.1.0 -> 1.3.1
|    +--- com.fasterxml.jackson.core:jackson-databind:2.8.3
|    |    +--- com.fasterxml.jackson.core:jackson-annotations:2.8.0 -> 2.8.3
|    |    \--- com.fasterxml.jackson.core:jackson-core:2.8.3
|    +--- org.springframework:spring-web:4.3.3.RELEASE
|    |    +--- org.springframework:spring-aop:4.3.3.RELEASE (*)
|    |    +--- org.springframework:spring-beans:4.3.3.RELEASE (*)
|    |    +--- org.springframework:spring-context:4.3.3.RELEASE (*)
|    |    \--- org.springframework:spring-core:4.3.3.RELEASE
|    +--- org.springframework:spring-webmvc:4.3.3.RELEASE
|    |    +--- org.springframework:spring-aop:4.3.3.RELEASE (*)
|    |    +--- org.springframework:spring-beans:4.3.3.RELEASE (*)
|    |    +--- org.springframework:spring-context:4.3.3.RELEASE (*)
|    |    +--- org.springframework:spring-core:4.3.3.RELEASE
|    |    +--- org.springframework:spring-expression:4.3.3.RELEASE (*)
|    |    \--- org.springframework:spring-web:4.3.3.RELEASE (*)
|    \--- org.springframework.boot:spring-boot-starter-tomcat:1.4.1.RELEASE
|         +--- org.apache.tomcat.embed:tomcat-embed-core:8.5.5
|         +--- org.apache.tomcat.embed:tomcat-embed-el:8.5.5
|         \--- org.apache.tomcat.embed:tomcat-embed-websocket:8.5.5
|              \--- org.apache.tomcat.embed:tomcat-embed-core:8.5.5
...

Why is not spring-boot-starter-tomcatexcluded from spring-boot-starter-web?

Answer 1

Yeah, I found the reason.

I also had a dependency compile("org.springframework.boot:spring-boot-starter-websocket"), which also depended on spring-boot-starter-tomcat. The gradle dependency conclusion leads me into thinking what spring-boot-starter-webis the reason that Tomcat is still there.

:

compile("org.springframework.boot:spring-boot-starter-websocket") {
    exclude module: "spring-boot-starter-tomcat"
}

, , - , , , . Gradle , ...

Answer 2

, spring -boot-- TOMCAT- - * , gradle

configurations {
  compile.exclude module: 'spring-boot-starter-tomcat'
  compile.exclude group: 'org.apache.tomcat'
}