一、简介
Scala-maven-plugin 是一个创造和管理 Scala 项目的maven插件,它可以自动生成基本项目结构、依赖配置、Scala文件等。使用它可以使我们专注于代码的实现而不是配置。
在Scala项目中,SBT是比较流行的构建工具,但是对于一些已经习惯于使用Maven的用户来说,Scala-maven-plugin 就成了不错的选择。
二、安装和配置scala-maven-plugin
首先需要在pom.xml文件中配置scala-maven-plugin,如下所示:
<plugin> <groupId>net.alchim31.maven</groupId> <artifactId>scala-maven-plugin</artifactId> <version>3.4.6</version> <executions> <execution> <goals> <goal>compile</goal> <goal>testCompile</goal> </goals> <configuration> <scalaVersion>2.13.2</scalaVersion> </configuration> </execution> </executions> </plugin>
上面的配置会将scala-maven-plugin的最新版本3.4.6下载到本地工程目录,同时还定义了启动Scala编译器的执行阶段。此外,也可以在 <configuration> 标签内添加其他的与 Scala 编译相关的设置。
三、scala-maven-plugin的命令行选项
scala-maven-plugin还提供了多个命令行选项,如下所示:
mvn scala:compile 编译src/main/scala下的源码 mvn scala:testCompile 编译src/test/scala下的源码 mvn scala:doc 生成api文档 mvn scala:run 运行Scala程序 mvn scala:console 进入scala交互式命令行
四、基本的scala-maven-plugin示例
下面我们来通过一个实际的例子,了解如何使用scala-maven-plugin。首先,我们需要创建一个空的Maven项目。
mvn archetype:generate -DgroupId=com.example -DartifactId=my-scala-project -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false
然后,在 pom.xml 文件中将 scala-maven-plugin 添加到 <build> 标签内:
<build> <plugins> <plugin> <groupId>net.alchim31.maven</groupId> <artifactId>scala-maven-plugin</artifactId> <version>3.4.6</version> <executions> <execution> <goals> <goal>compile</goal> </goals> </execution> </executions> </plugin> </plugins> </build>
接着,在src/main/scala目录下创建一个名为HelloWorld.scala的文件,内容如下:
object HelloWorld { def main(args: Array[String]): Unit = { println("Hello, world!") } }
现在就可以使用下面的命令来编译和运行文件了:
mvn scala:compile mvn scala:run -DmainClass=HelloWorld
如果一切顺利,你将会看到程序输出:
[INFO] Scanning for projects... [INFO] [INFO] -------------------------< com.example:my-scala-project >------------------ [INFO] Building my-scala-project 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ my-scala-project --- [INFO] Using 'UTF-8' encoding to copy filtered resources. [INFO] skip non existing resourceDirectory /Users/haochu/my-scala-project/src/main/resources [INFO] [INFO] --- scala-maven-plugin:3.4.6:compile (default-cli) @ my-scala-project --- [INFO] /Library/Java/JavaVirtualMachines/jdk1.8.0_241.jdk/Contents/Home/jre/../bin/java -cp /Users/haochu/.m2/repository/org/scala-lang/scala-library/2.13.2/scala-library-2.13.2.jar:/Users/haochu/.m2/repository/org/scala-lang/scala-compiler/2.13.2/scala-compiler-2.13.2.jar:/Users/haochu/.m2/repository/org/scala-lang/modules/scala-xml_2.13/1.3.0/scala-xml_2.13-1.3.0.jar:/Users/haochu/.m2/repository/org/scala-lang/modules/scala-parser-combinators_2.13/1.1.2/scala-parser-combinators_2.13-1.1.2.jar:/Users/haochu/my-scala-project/target/classes:/Users/haochu/.m2/repository/org/apache/maven/maven-plugin-api/3.3.9/maven-plugin-api-3.3.9.jar:/Users/haochu/.m2/repository/org/apache/maven/maven-model/3.3.9/maven-model-3.3.9.jar:/Users/haochu/.m2/repository/org/apache/maven/maven-artifact/3.3.9/maven-artifact-3.3.9.jar:/Users/haochu/.m2/repository/org/eclipse/sisu/org.eclipse.sisu.inject/0.3.4/org.eclipse.sisu.inject-0.3.4.jar:/Users/haochu/.m2/repository/org/eclipse/sisu/org.eclipse.sisu.plexus/0.3.4/org.eclipse.sisu.plexus-0.3.4.jar:/Users/haochu/.m2/repository/org/codehaus/plexus/plexus-component-annotations/1.7.1/plexus-component-annotations-1.7.1.jar:/Users/haochu/.m2/repository/org/sonatype/plexus/plexus-sec-dispatcher/1.4/plexus-sec-dispatcher-1.4.jar:/Users/haochu/.m2/repository/org/sonatype/plexus/plexus-cipher/1.4/plexus-cipher-1.4.jar net.alchim31.maven:scala-maven-plugin:3.4.6:compile [INFO] Compiling 1 Scala source to /Users/haochu/my-scala-project/target/classes ... [INFO] Done compiling. [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 3.149 s [INFO] Finished at: 2021-03-07T12:00:20+08:00 [INFO] ------------------------------------------------------------------------ Hello, world!
五、总结
通过本文的介绍,你已经可以使用scala-maven-plugin在maven项目中集成Scala了。它不仅可以自动生成项目结构,还可以使用命令行选项执行Scala编译、运行程序和生成API文档等。希望本文对你有所帮助,也欢迎分享你在使用Scala-maven-plugin时的经验和技巧。