Java – exclude Tomcat dependencies from spring boot in gradle

I'm using @ L_ 419_ 0 @ boot and jetty, I can't seem to exclude all Tomcat dependencies in the gradle build file

build. Relevant parts of 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 the gradle dependency, the Tomcat part still exists and causes 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 can't spring boot starter Tomcat be excluded from spring boot starter web?

Solution

Aha, I found the reason

I also have a compiler ("org. Springframework. Boot: spring boot starter websocket") dependency, which depends on spring boot starter Tomcat Gradle's reliance on output misleads me that spring boot starter web is the reason why Tomcat still exists

I have to add the following:

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

The lesson learned is that when you want to exclude something, carefully check all dependencies to ensure that it is excluded from all locations And the gradle dependency output can be improved to reduce misleading