Build.scala, % 和 %% 符号含义 [英] Build.scala, % and %% symbols meaning

问题描述

我是 Play 的新手！Framework 2.1(java 版)并且没有使用 scala 的经验.我不明白在 Build.scala 中 % 和 %% 是什么以及什么意思.我用谷歌搜索了它们，但找不到它们的含义.

I'm new to Play! Framework 2.1 (java version) and have no experience with scala. I don't understand what are and what does % and %% mean in Build.scala. I googled about them but couldn't find their meaning.

在我的 Build.scala 文件中，我有:

In my Build.scala file I have:

"org.hibernate" % "hibernate-entitymanager" % "4.1.0.Final",
"com.typesafe" %% "play-plugins-mailer" % "2.1"

为什么第一行使用单个 % 符号而第二行使用两个百分比符号 %%?它们有什么用?

Why the first line uses a single % symbol and the second one uses two percent symbols %%? What are they for?

推荐答案

来自官方文档:

http://www.playframework.com/documentation/2.1.1/SBTDependencies

使用 %%

如果你使用groupID %% artifactID % revision 而不是groupID % artifactID % revision(区别在于后面的双%%groupID)，SBT 会将您项目的 Scala 版本添加到工件中姓名.这只是一个捷径.

If you use groupID %% artifactID % revision instead of groupID % artifactID % revision (the difference is the double %% after the groupID), SBT will add your project’s Scala version to the artifact name. This is just a shortcut.

您可以在没有 %% 的情况下编写此代码:

You could write this without the %%:

val appDependencies = Seq(
  "org.scala-tools" % "scala-stm_2.9.1" % "0.3"
)

假设您构建的 scalaVersion 是 2.9.1，以下是相同的:

Assuming the scalaVersion for your build is 2.9.1, the following is identical:

val appDependencies = Seq(
  "org.scala-tools" %% "scala-stm" % "0.3"
)

如上所示，如果使用 %%，则不必指定版本.

As you can see above, if you use %%, you don't have to specify the version.

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