sbt 如何生成多个具有不同分类器和不同主类的 jar? [英] How can sbt generate several jars with different classifiers and different main classes?
问题描述
我正在使用 sbt 来打包我的项目.但是,我的项目中有两个主要类基于相同的来源.我想为这两个主要类创建两个具有不同分类器的 jar.由于这两个主要类共享项目中的大部分源代码,因此我无法将它们分成两个项目.因此,有人可以帮我修改 build.sbt 以实现这样的目标吗?
I am using sbt to package my project. However there are two main classes in my project based on the same source. And I want to create two jars with different classifiers for these two main classes. Since these two main classes shares most source code in the project, I cannot separate them into two projects. Therefore, could anyone help me modify the build.sbt to achieve such a goal?
推荐答案
TL;DR:您需要做的就是在 sbt
中定义 mainClass
.
TL;DR: All you need to do is define the mainClass
in sbt
.
现在让我们描述如何去做.
Now let's describe how to do it.
在根目录,我们需要创建sbt.build
.其内容将是:
At the root, we need to create sbt.build
. Its content is going to be:
lazy val root = project.settings(
version := "0.0.1-SNAPSHOT",
scalaVersion := "2.12.12"
).aggregate(moduleA, moduleB)
lazy val commons = project
lazy val moduleA = project.settings(mainClass in (Compile, packageBin) := Some("MainClassA")).dependsOn(commons)
lazy val moduleB = project.settings(mainClass in (Compile, packageBin) := Some("MainClassB")).dependsOn(commons)
您可以阅读更多关于 sbt 聚合,以及关于 如何指定要运行的主要方法/类.该项目的结构如下:
You can read more about sbt aggregation, and about How to specify a main method/class to run. The project is going to be structured as follows:
/
|-build.sbt
|-project
|-plugins.sbt
|-commons
|-src
|-main
|scala
|-SomeClass.scala
|-moduleA
|-src
|-main
|-scala
|-MainClassA.scala
|-moduleB
|-src
|-main
|-scala
|-MainClassB.scala
SomeClass.scala
的内容是:
object SomeClass {
def doPrint() = {
println("I am in commons")
}
}
MainClassA.scala
的内容是(假设scala版本到2.12,scala 2.13不需要扩展App annymore):
The content of MainClassA.scala
is(assuming scala version is up to 2.12 . In scala 2.13 you do not need to extend App annymore.):
object MainClassA extends App {
override def main(args: Array[String]): Unit = {
SomeClass.doPrint()
println("Hello MainClassA")
}
}
MainClassB.scala
的内容是(这里注释相同):
The content of MainClassB.scala
is(same comment here):
object MainClassB extends App {
override def main(args: Array[String]): Unit = {
SomeClass.doPrint()
println("Hello MainClassB")
}
}
plugins.sbt
的内容为:
addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.15.0")
现在,一切准备就绪,我们需要执行.我们安装了 sbt-assembly
插件,因此我们可以运行:sbt assembly.
Now, we have everything ready, and we need to execute. We installed the sbt-assembly
plugin, hence we can run: sbt assembly.
这将创建一些文件,但我们会对 2 感兴趣:
This will create some files, but we will be interested in 2:
./moduleA/target/scala-2.12/moduleA-assembly-0.1.0-SNAPSHOT.jar
./moduleB/target/scala-2.12/moduleB-assembly-0.1.0-SNAPSHOT.jar
然后,当运行 java -jar ./moduleA/target/scala-2.12/moduleA-assembly-0.1.0-SNAPSHOT.jar
时,我们得到:
Then, when running java -jar ./moduleA/target/scala-2.12/moduleA-assembly-0.1.0-SNAPSHOT.jar
we get:
I am in commons
Hello MainClassA
并且,当运行 java -jar ./moduleB/target/scala-2.12/moduleB-assembly-0.1.0-SNAPSHOT.jar
时,我们得到:
And, when running java -jar ./moduleB/target/scala-2.12/moduleB-assembly-0.1.0-SNAPSHOT.jar
we get:
I am in commons
Hello MainClassB
附言真的不建议从同一个构建中创建多个 jar.它会造成巨大的风险,即错过依赖项并获得缺少方法/类的运行时异常.
P.S. It is really not recommended to create multiple jars from the same build. It creates a huge risk to miss dependencies and get a runtime exception of missing methods/classes.
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