Spark，Idea中编写Spark程序 2

Idea中编写Spark程序

一、修改pom.xml文件

<build><sourceDirectory>src/main/scala</sourceDirectory><testSourceDirectory>src/test/scala</testSourceDirectory>
<!--        添加必要的插件以打包scala程序--><plugins><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></execution></executions><configuration><args><arg>-dependencyfile</arg><arg>${project.build.directory}/.scala_dependencies</arg></args></configuration></plugin><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-shade-plugin</artifactId><version>2.4.3</version><executions><execution><phase>package</phase><goals><goal>shade</goal></goals></execution></executions><configuration><filters><filter><artifact>*:*</artifact><excludes><exclude>META-INF/*.SF</exclude><exclude>META-INF/*.DSA</exclude><exclude>META-INF/*.RSA</exclude></excludes></filter></filters><transformers><transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer"><mainClass></mainClass></transformer></transformers></configuration></plugin></plugins></build>

二、修改代码

修改两个地方：输入目录改成args(0), 输出的目录改成args(1)。

import org.apache.spark.{SparkConf, SparkContext}object WordCount_online {// 写一个spark程序，统计input目录下所有文本文件中单词的词频// 把结果保存在output下def main(args: Array[String]): Unit = {
//    println("hello spark!")// 配置 Spark 应用程序val conf = new SparkConf().setAppName("WordCount_online")// 创建 SparkContext 对象val sc = new SparkContext(conf)// 读取目录下的所有文本文件val textFiles = sc.wholeTextFiles(args(0))// 提取文本内容并执行 WordCount 操作val counts = textFiles.flatMap { case (_, content) => content.split("\\s+") }.map(word => (word, 1)).reduceByKey(_ + _)// 将所有分区的数据合并成一个分区val singlePartitionCounts = counts.coalesce(1)// 保存结果到文件singlePartitionCounts.saveAsTextFile(args(1))// 停止 SparkContextsc.stop()}
}