最近因爲要使用Spark作POC,在本地搭建了相應的開發環境,Spark自己是使用Scala語言編寫的,固然也能夠使用java來開發spark項目,但使用scala語言來開發更加簡潔,本文在IDEA開發工具中使用Maven來建立Scala工程html
1:安裝Java SDK,Scala,及IDEA 集成開發環境java
JDK下載地址:http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.htmlshell
Scala下載地址:http://www.scala-lang.org/download/all.htmlapache
Intellij IDEA下載地址:https://www.jetbrains.com/idea/download/download-thanks.html架構
如下是我測試環境中 java 及 scala的版本:oracle
IDEA使用的是社區版本:IDEA 2017.3.5 (Community Edition)eclipse
2:Spark的安裝jvm
下載spark:https://spark.apache.org/downloads.html,選擇相應的版本,這裏選擇了2.2.1版本 spark-2.2.1-bin-hadoop2.7,並解壓到指定的目錄,添加環境變量:maven
SPARK_HOME:D:\Application\spark-2.2.1-bin-hadoop2.7ide
並添加如下路徑到Path變量中:%SPARK_HOME%\bin
這樣能夠在命令行中啓動命令:spark-shell
3:Scala插件的安裝
在IDEA中選擇 Configure -> Plugins,搜索scala,點擊安裝:
4:使用Maven來建立Scala 工程
點擊 Next,設置好GroupId及ArtifactId,一路點擊到結束,期間根據實際狀況能夠修改Project name及代碼的路徑,最後生成Scala架構的代碼目錄及默認的pom.xml文件,在這裏須要注意一點,Scala的本機安裝的版本和Scala插件的版本不一致的問題,查看生成的默認pom.xml文件以下,發現版本使用的是2.7.0,而前面本機安裝的是2.11.8 ,
這樣建立的項目運行時會失敗,提示 "Error: Could not find or load main class ..."
查看前面安裝的Scala版本,相應的修改pom文件中的版本號爲2.11.8,這就出現了另一個問題,從Scala2.9之後,已經廢棄了Application類,而是使用了新的類App,因而修改代碼
object App extends App {
println( "Hello World!" )
}
運行項目,單元測試報錯,提示scala signature 版本錯誤,先刪除MySpec.scala文件
修改pom文件,
5:添加對spark的支持,本地測試文件單詞統計
修改pom.xml
添加屬性 spark 版本,爲本機安裝的spark版本
<spark.version>2.2.1</spark.version>
添加依賴庫
<dependency> <groupId>org.apache.spark</groupId> <artifactId>spark-core_2.11</artifactId> <version>${spark.version}</version> </dependency>
完整的pom.xml以下所示:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>mytest</groupId> <artifactId>myproject</artifactId> <version>1.0-SNAPSHOT</version> <inceptionYear>2008</inceptionYear> <properties> <scala.version>2.11.8</scala.version> <spark.version>2.2.1</spark.version> </properties> <repositories> <repository> <id>scala-tools.org</id> <name>Scala-Tools Maven2 Repository</name> <url>http://scala-tools.org/repo-releases</url> </repository> </repositories> <pluginRepositories> <pluginRepository> <id>scala-tools.org</id> <name>Scala-Tools Maven2 Repository</name> <url>http://scala-tools.org/repo-releases</url> </pluginRepository> </pluginRepositories> <dependencies> <dependency> <groupId>org.apache.spark</groupId> <artifactId>spark-core_2.11</artifactId> <version>${spark.version}</version> </dependency> <dependency> <groupId>org.scala-lang</groupId> <artifactId>scala-library</artifactId> <version>${scala.version}</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.4</version> <scope>test</scope> </dependency> <dependency> <groupId>org.specs</groupId> <artifactId>specs</artifactId> <version>1.2.5</version> <scope>test</scope> </dependency> </dependencies> <build> <sourceDirectory>src/main/scala</sourceDirectory> <testSourceDirectory>src/test/scala</testSourceDirectory> <plugins> <plugin> <groupId>org.scala-tools</groupId> <artifactId>maven-scala-plugin</artifactId> <executions> <execution> <goals> <goal>compile</goal> <goal>testCompile</goal> </goals> </execution> </executions> <configuration> <scalaVersion>${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>${scala.version}</scalaVersion> </configuration> </plugin> </plugins> </reporting> </project>
修改scala代碼,引入spark庫:
package mytest import org.apache.spark._ object wordcount { def main(args: Array[String]) { var masterUrl = "local[1]" var inputPath = "D:\\temp\\mytext.txt" var outputPath = "D:\\temp\\output" println(s"masterUrl:${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) } }
再次運行工程,能夠在窗口中看到已經成功運行spark,對輸入的文本進行詞彙統計,此時,spark運行的是本地模式,使用的是本地文件做爲輸入
在輸出目錄,能夠看到程序運行的結果