gradle war: how to build jar, not classes

问题

Gradle war plugin: how to build a jar and add it to war?

projectRoot/
        src/main/java
        src/main/resources
        src/main/webapp

1. build a jar (foo.jar) from the java source code and resources.

2. add the jar under the WEB-INF/lib of the war.

   WEB-INF/lib/foo.jar

The war task will not build a jar by default, and add all java classes and resources under WEB-INF/classes.

UPDATE

The War plugin extends the Java plugin to add support for assembling web
application WAR files. It disables the default JAR archive generation of the 
Java plugin and adds a default WAR archive task.

There is a way to enable the Jar generation and let task war depends on task jar?

来源：https://stackoverflow.com/questions/44748067/gradle-war-how-to-build-jar-not-classes