scala eclipse sbt 应用程序开发

搭建Eclipse开发Scala应用程序的一般步骤

一、环境准备：

2、Scala IDE for Eclipse :scala-ide.org

4、Sbt Eclipse : https://github.com/typesafehub/sbteclipse   typesafe的一个sbt for eclipse的助手，可以帮助生成eclipse

我的，Scala版本是2.10.3， Sbt版本是0.13

二、sbt生成scala eclipse项目：

我们想要在Eclipse里开发scala应用并符合sbt发布程序的文件结构(类似Maven结构)，除了手工建立文件结构，还可以采用sbt eclipse的配置方法。

2.1、添加sbt eclipse插件

有2种配置方式：

一种是在 ~/.sbt/0.13/plugins//build.sbt 里配置addPlugin,这种做法是全局的插件，即对本机所有sbt项目均使用。

另一种是每个项目不一样的plugins，则是在每个项目跟目录下project/plugins.sbt里进行插件配置。

plugins.sbt里面内容配置，添加插件：

addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "2.4.0")

2.2、生成eclipse项目文件

然后进入到根目录sbt,成功进入sbt，运行eclipse命令生成eclipse的.classpath等eclipse相关文件：

可以看到和maven的目录结构是相似的：

src

├── main

│   ├── java

│   └── scala

└── test

├── java

└── scala

发现没有resouces目录：

在跟目录的build.sbt里添加：

EclipseKeys.createSrc := EclipseCreateSrc.Default + EclipseCreateSrc.Resource

再执行sbt eclipse

src/

├── main

│   ├── java

│   ├── resources

│   └── scala

└── test

├── java

├── resources

└── scala

2.3、导入Eclipse中

我们进入Eclipse，利用导入向导的import existing project into workspace这一项进行导入。

三、开发与部署

下面准备用一个实际例子演示在Scala里开发的一般步骤，最近用到scala里的json，就用json4s这个json lib来开发一个解析json的例子，json4s地址： https://github.com/json4s/json4s

3.1、添加依赖

我们如果想使用第三方的类，就需要添加依赖关系，和GAV坐标，这个再熟悉不过，我们需要编辑根目录下的build.sbt文件，添加依赖：

这里name,version,scalaVersion要注意每个间隔一行，其它的也是，不然会出错。

libraryDependencies是添加依赖的地方：我们添加2个。

resolvers是仓库地址，这里配置了多个。

name := "shengli_test_sbt"version := "1.0"scalaVersion := "2.10.3"EclipseKeys.createSrc := EclipseCreateSrc.Default +EclipseCreateSrc.Resource

libraryDependencies++=Seq("org.json4s" %% "json4s-native" % "3.2.10","org.json4s" %% "json4s-jackson" % "3.2.10")

resolvers++=Seq(//HTTPS is unavailable for Maven Central

"Maven Repository" at "http://repo.maven.apache.org/maven2","Apache Repository" at "https://repository.apache.org/content/repositories/releases","JBoss Repository" at "https://repository.jboss.org/nexus/content/repositories/releases/","MQTT Repository" at "https://repo.eclipse.org/content/repositories/paho-releases/","Cloudera Repository" at "http://repository.cloudera.com/artifactory/cloudera-repos/",//For Sonatype publishing//"sonatype-snapshots" at "https://oss.sonatype.org/content/repositories/snapshots",//"sonatype-staging" at "https://oss.sonatype.org/service/local/staging/deploy/maven2/",//also check the local Maven repository ~/.m2

Resolver.mavenLocal

)

再次运行sbt eclipse，则依赖的jar包会自动加载到classpath：

3.2、测试程序

一个简单的解析Json的程序，程序很简单，这里就不解释了。

packagecom.shengli.jsonimportorg.json4s._importorg.json4s.JsonDSL._importorg.json4s.jackson.JsonMethods._

object JsonSbtTestextendsApplication{case classWinner(id: Long, numbers: List[Int])case classLotto(id: Long, winningNumbers: List[Int], winners: List[Winner], drawDate: Option[java.util.Date])

val winners= List(Winner(23, List(2, 45, 34, 23, 3, 5)), Winner(54, List(52, 3, 12, 11, 18, 22)))

val lotto= Lotto(5, List(2, 45, 34, 23, 7, 5, 3), winners, None)

val json=("lotto" ->("lotto-id" -> lotto.id) ~("winning-numbers" -> lotto.winningNumbers) ~("draw-date" -> lotto.drawDate.map(_.toString)) ~("winners" ->lotto.winners.map { w=>(("winner-id" -> w.id) ~("numbers" ->w.numbers))}))

println(compact(render(json)))

println(pretty(render(json)))

}

至此我们在eclipse能运行Run as Scala Application，但是如何加依赖打包发布呢？

3.3、Assembly

还记得Spark里面的assembly吗？那个就是发布用的，sbt本身支持的clean compile package之类的命令，但是带依赖的one jar打包方式还是assembly比较成熟。

clean

Deletes all generated files (in the target directory).

compile

Compiles the main sources (in src/main/scala and src/main/java directories).

test

Compiles and runs all tests.

console

Starts the Scala interpreter with a classpath including the compiled sources and all dependencies. To return to sbt, type :quit , Ctrl+D (Unix), or Ctrl+Z (Windows).

run *

Runs the main class for the project in the same virtual machine as sbt.

package

Creates a jar file containing the files in src/main/resources and the classes compiled from src/main/scala and src/main/java .

help

Displays detailed help for the specified command. If no command is provided, displays brief descriptions of all commands.

reload

Reloads the build definition ( build.sbt , project/*.scala , project/*.sbt files). Needed if you change the build definition.

Assembly ：

Assembly是作为一种插件的，所以要在project下面的plugins.sbt里面配置，至此plugins.sbt文件里内容如下：

resolvers += Resolver.url("artifactory", url("http://scalasbt.artifactoryonline.com/scalasbt/sbt-plugin-releases"))(Resolver.ivyStylePatterns)

resolvers+= "Typesafe Repository" at "http://repo.typesafe.com/typesafe/releases/"addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "2.4.0")

addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.11.2")

除了插件的配置之外，还需要配置跟目录下build.sbt，支持assembly，在文件头部加入：

importAssemblyKeys._

assemblySettings

至此build.sbt文件内容如下：importAssemblyKeys._

assemblySettings

name := "shengli_test_sbt"version := "1.0"scalaVersion := "2.10.3"EclipseKeys.createSrc := EclipseCreateSrc.Default +EclipseCreateSrc.Resource

libraryDependencies++=Seq("org.json4s" %% "json4s-native" % "3.2.10","org.json4s" %% "json4s-jackson" % "3.2.10")

resolvers++=Seq(//HTTPS is unavailable for Maven Central

"Maven Repository" at "http://repo.maven.apache.org/maven2","Apache Repository" at "https://repository.apache.org/content/repositories/releases","JBoss Repository" at "https://repository.jboss.org/nexus/content/repositories/releases/","MQTT Repository" at "https://repo.eclipse.org/content/repositories/paho-releases/","Cloudera Repository" at "http://repository.cloudera.com/artifactory/cloudera-repos/",//For Sonatype publishing//"sonatype-snapshots" at "https://oss.sonatype.org/content/repositories/snapshots",//"sonatype-staging" at "https://oss.sonatype.org/service/local/staging/deploy/maven2/",//also check the local Maven repository ~/.m2

Resolver.mavenLocal

)

运行sbt assembly命令进行发布：

>assembly

[info] Updating {file:/home/victor/workspace/test_sbt/}test_sbt...

[info] Resolving org.fusesource.jansi#jansi;1.4...

[info] Done updating.

[info] Compiling1 Scala source to /home/victor/workspace/test_sbt/target/scala-2.10/classes...

[warn] there were1 deprecation warning(s); re-run with -deprecation fordetails

[warn] one warning found

[info] Including: scala-compiler-2.10.0.jar

[info] Including: scala-library-2.10.3.jar

[info] Including: json4s-native_2.10-3.2.10.jar

[info] Including: json4s-core_2.10-3.2.10.jar

[info] Including: json4s-ast_2.10-3.2.10.jar

[info] Including: paranamer-2.6.jar

[info] Including: scalap-2.10.0.jar

[info] Including: jackson-databind-2.3.1.jar

[info] Including: scala-reflect-2.10.0.jar

[info] Including: jackson-annotations-2.3.0.jar

[info] Including: json4s-jackson_2.10-3.2.10.jar

[info] Including: jackson-core-2.3.1.jar

[info] Checking every*.class/*.jar file's SHA-1.

[info] Merging files...

[warn] Merging 'META-INF/NOTICE' with strategy 'rename'

[warn] Merging 'META-INF/LICENSE' with strategy 'rename'

[warn] Merging 'META-INF/MANIFEST.MF' with strategy 'discard'

[warn] Merging 'rootdoc.txt' with strategy 'concat'

[warn] Strategy 'concat' was applied to a file

[warn] Strategy 'discard' was applied to a file

[warn] Strategy 'rename' was applied to 2 files

[info] SHA-1: d4e76d7b55548fb2a6819f2b94e37daea9421684

[info] Packaging /home/victor/workspace/test_sbt/target/scala-2.10/shengli_test_sbt-assembly-1.0.jar ...

[info] Done packaging.

[success] Total time: 39 s, completed Aug 4, 2014 1:26:11 AM

四、总结

本文介绍了在Eclipse里利用Sbt构建开发Scala程序的一般步骤，并用实例讲解了整个流程。

用sbt eclipse插件生成sbt文件目录结构，sbt eclipse命令来生成更新jar包依赖。

用assebly插件对scala应用进行打包发布。