IntelliJ IDEA下 Maven 创建 Scala 项目

环境：IntelliJ IDEA
版本：Spark-2.2.1 Scala-2.11.0

利用 Maven 第一次创建 Scala 项目也遇到了许多坑

创建一个 Scala 的 WordCount 程序

第一步：IntelliJ IDEA下安装 Scala 插件

安装完 Scala 插件完成

第二步：Maven 下 Scala 下的项目创建

正常创建 Maven 项目（不会的看另一篇 Maven 配置）

第三步：Scala 版本的下载及配置

通过Spark官网下载页面http://spark.apache.org/downloads.html 可知“Note: Starting version 2.0, Spark is built with Scala 2.11 by default.”，建议下载Spark2.2对应的 Scala 2.11。

登录Scala官网http://www.scala-lang.org/，单击download按钮，然后再“Other Releases”标题下找到“下载2.11.0

根据自己的系统下载相应的版本
接下来就是配置Scala 的环境变量（跟 jdk 的配置方法一样）

输入 Scala -version 查看是否配置成功
会显示
Scala code runner version 2.11.0 – Copyright 2002-2013, LAMP/EPFL

选择自己安装 Scala 的路径

第四步：编写 Scala 程序

将其他的代码删除，不然在编辑的时候会报错

配置 pom.xml文件
在里面添加一个 Spark

  <properties>
    <scala.version>2.11.0</scala.version>
    <spark.version>2.2.1</spark.version>
  </properties>
  <dependency>
      <groupId>org.apache.spark</groupId>
      <artifactId>spark-core_2.11</artifactId>
      <version>${spark.version}</version>
    </dependency>

具体的 pom.xml 内容

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>cn.spark</groupId>
  <artifactId>Spark</artifactId>
  <version>1.0-SNAPSHOT</version>
  <inceptionYear>2008</inceptionYear>
  <properties>
    <scala.version>2.11.0</scala.version>
    <spark.version>2.2.1</spark.version>
  </properties>


  <pluginRepositories>
    <pluginRepository>
      <id>scala-tools.org</id>
      <name>Scala-Tools Maven2 Repository</name>
      <url>http://scala-tools.org/repo-releases</url>
    </pluginRepository>
  </pluginRepositories>

  <dependencies>
    <dependency>
      <groupId>org.scala-lang</groupId>
      <artifactId>scala-library</artifactId>
      <version>${scala.version}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.spark</groupId>
      <artifactId>spark-core_2.11</artifactId>
      <version>${spark.version}</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.4</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.specs</groupId>
      <artifactId>specs</artifactId>
      <version>1.2.5</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <sourceDirectory>src/main/scala</sourceDirectory>
    <testSourceDirectory>src/test/scala</testSourceDirectory>
    <plugins>
      <plugin>
        <groupId>org.scala-tools</groupId>
        <artifactId>maven-scala-plugin</artifactId>
        <executions>
          <execution>
            <goals>
              <goal>compile</goal>
              <goal>testCompile</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <scalaVersion>${scala.version}</scalaVersion>
          <args>
            <arg>-target:jvm-1.5</arg>
          </args>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-eclipse-plugin</artifactId>
        <configuration>
          <downloadSources>true</downloadSources>
          <buildcommands>
            <buildcommand>ch.epfl.lamp.sdt.core.scalabuilder</buildcommand>
          </buildcommands>
          <additionalProjectnatures>
            <projectnature>ch.epfl.lamp.sdt.core.scalanature</projectnature>
          </additionalProjectnatures>
          <classpathContainers>
            <classpathContainer>org.eclipse.jdt.launching.JRE_CONTAINER</classpathContainer>
            <classpathContainer>ch.epfl.lamp.sdt.launching.SCALA_CONTAINER</classpathContainer>
          </classpathContainers>
        </configuration>
      </plugin>
    </plugins>
  </build>
  <reporting>
    <plugins>
      <plugin>
        <groupId>org.scala-tools</groupId>
        <artifactId>maven-scala-plugin</artifactId>
        <configuration>
          <scalaVersion>${scala.version}</scalaVersion>
        </configuration>
      </plugin>
    </plugins>
  </reporting>
</project>

编写 WordCount 文件

package cn.spark

import org.apache.spark.{SparkConf, SparkContext}

/**
  * Created by hubo on 2018/1/13
  */
object WordCount {
  def main(args: Array[String]) {
    var masterUrl = "local"
    var inputPath = "/Users/huwenbo/Desktop/a.txt"
    var outputPath = "/Users/huwenbo/Desktop/out"

    if (args.length == 1) {
      masterUrl = args(0)
    } else if (args.length == 3) {
      masterUrl = args(0)
      inputPath = args(1)
      outputPath = args(2)
    }

    println(s"masterUrl:$masterUrl, inputPath: $inputPath, outputPath: $outputPath")
    val sparkConf = new SparkConf().setMaster(masterUrl).setAppName("WordCount")
    val sc = new SparkContext(sparkConf)

    val rowRdd = sc.textFile(inputPath)
    val resultRdd = rowRdd.flatMap(line => line.split("\\s+"))
      .map(word => (word, 1)).reduceByKey(_ + _)

    resultRdd.saveAsTextFile(outputPath)
  }
}

var masterUrl = “local”
local代表自己本地运行，在 hadoop 上运行添加相应地址

在配置中遇到的错误，会写在另一篇文章里。