前提：安装scala插件；能读写HDFS文件

    1. 创建maven项目，修改java目录为scala，添加项目框架scala
    1. pom.xml添加依赖
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    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <scala.version>2.12.10</scala.version>
        <spark.version>2.4.5</spark.version>
        <hadoop.version>2.9.2</hadoop.version>
        <encoding>UTF-8</encoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>${scala.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-core_2.12</artifactId>
            <version>${spark.version}</version>
        </dependency>
    </dependencies>

    <build>
        <pluginManagement>
            <plugins>
                <!-- 编译scala的插件 -->
                <plugin>
                    <groupId>net.alchim31.maven</groupId>
                    <artifactId>scala-maven-plugin</artifactId>
                    <version>3.2.2</version>
                </plugin>
                <!-- 编译java的插件 -->
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.5.1</version>
                </plugin>
            </plugins>
        </pluginManagement>
        <plugins>
            <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <id>scala-compile-first</id>
                        <phase>process-resources</phase>
                        <goals>
                            <goal>add-source</goal>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>scala-test-compile</id>
                        <phase>process-test-resources</phase>
                        <goals>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <executions>
                    <execution>
                        <phase>compile</phase>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <!-- 打jar插件 -->
            <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>
                        <configuration>
                            <filters>
                                <filter>
                                    <artifact>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
    1. 在resource目录下创建core-site.xml，内容为虚拟机环境上Hadoop的配置文件core-site.xml
    1. 创建scal对象WordCount
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    package cn.lagou.sparkcore

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

    object WordCount {
      def main(args: Array[String]): Unit = {

        val conf = new SparkConf().setMaster("local").setAppName("WordCount")
        val sc = new SparkContext(conf)

        //本地文件
        // val lines: RDD[String] = sc.textFile("data/wc.dat")

        //hdfs文件  --无配置文件
        // val lines: RDD[String] = sc.textFile("hdfs://linux121:9000/wcinput/wc.txt")

        //hdfs文件  --有配置文件（src/main/resources/core-site.xml）
        val lines: RDD[String] = sc.textFile("/wcinput/wc.txt")

        lines.flatMap(_.split(" ")).map((_, 1)).reduceByKey(_+_).collect().foreach(println)
        sc.stop()
      }
    }
    1. 链接源码