一、多表關聯

輸入是兩個文件，一個代表工廠表，包含工廠名列和地址編號列；另一個代表地址表，包含地址名列和地址編號列。要求從輸入數據中找出工廠名和地址名的對應關系，輸出"工廠名——地址名"表

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二、maven設置

<?xml version="1.0" encoding="UTF-8"?><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/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.mk</groupId><artifactId>spark-test</artifactId><version>1.0</version><name>spark-test</name><url>http://spark.mk.com</url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><maven.compiler.source>1.8</maven.compiler.source><maven.compiler.target>1.8</maven.compiler.target><scala.version>2.11.1</scala.version><spark.version>2.4.4</spark.version><hadoop.version>2.6.0</hadoop.version></properties><dependencies><!-- scala依賴--><dependency><groupId>org.scala-lang</groupId><artifactId>scala-library</artifactId><version>${scala.version}</version></dependency><!-- spark依賴--><dependency><groupId>org.apache.spark</groupId><artifactId>spark-core_2.11</artifactId><version>${spark.version}</version></dependency><dependency><groupId>org.apache.spark</groupId><artifactId>spark-sql_2.11</artifactId><version>${spark.version}</version></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.11</version><scope>test</scope></dependency></dependencies><build><pluginManagement><plugins><plugin><artifactId>maven-clean-plugin</artifactId><version>3.1.0</version></plugin><plugin><artifactId>maven-resources-plugin</artifactId><version>3.0.2</version></plugin><plugin><artifactId>maven-compiler-plugin</artifactId><version>3.8.0</version></plugin><plugin><artifactId>maven-surefire-plugin</artifactId><version>2.22.1</version></plugin><plugin><artifactId>maven-jar-plugin</artifactId><version>3.0.2</version></plugin></plugins></pluginManagement></build> </project>

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三、編程代碼?

public class MultiTableJoinApp implements SparkConfInfo {public static void main(String[] args) {String factoryFilePath = "E:\\spark\\factory.txt";SparkSession sparkSession = new MultiTableJoinApp().getSparkConf("MultiTableJoinApp");JavaPairRDD<String, String> addressFactoryRdd = sparkSession.sparkContext().textFile(factoryFilePath, 4).toJavaRDD().flatMap(v -> Arrays.asList(v.split("\n")).iterator()).mapToPair(v -> {if(v.matches("\\s+factoryname\\s+addressed\\s+")){return null;}String[] data = v.trim().split("\\s{2,}");if (data.length != 2) {return null;}return new Tuple2<>(data[1],data[0]);}).filter(v -> v != null);String addressFilePath = "E:\\spark\\address.txt";JavaPairRDD<String, String> addressNameRdd = sparkSession.sparkContext().textFile(addressFilePath, 4).toJavaRDD().flatMap(v -> Arrays.asList(v.split("\n")).iterator()).mapToPair(v -> {if(v.matches("\\s+addressID\\s+addressname\\s+")){return null;}String[] data = v.trim().split("\\s{2,}");if (data.length != 2) {return null;}return new Tuple2<>(data[0],data[1]);}).filter(v -> v != null);JavaPairRDD<String, Tuple2<String, String> > joinRdd = addressFactoryRdd.join(addressNameRdd);List<Tuple2<String, String>> childGrand = joinRdd.mapToPair(v->new Tuple2<>(v._2._1, v._2._2)).sortByKey(true).collect();System.out.println("factoryname\t\taddressname");childGrand.forEach(v -> System.out.println(v._1 + "\t\t" + v._2));sparkSession.stop();} }public interface SparkConfInfo {default SparkSession getSparkConf(String appName){SparkConf sparkConf = new SparkConf();if(System.getProperty("os.name").toLowerCase().contains("win")) {sparkConf.setMaster("local[4]");System.out.println("使用本地模擬是spark");}else{sparkConf.setMaster("spark://hadoop01:7077,hadoop02:7077,hadoop03:7077");sparkConf.set("spark.driver.host","192.168.150.1");//本地ip，必須與spark集群能夠相互訪問，如：同一個局域網sparkConf.setJars(new String[] {".\\out\\artifacts\\spark_test\\spark-test.jar"});//項目構建生成的路徑}SparkSession session = SparkSession.builder().appName(appName).config(sparkConf).config(sparkConf).getOrCreate();return session;} }

factory.txt文件內容

factoryname addressed Beijing Red Star 1 Shenzhen Thunder 3 Guangzhou Honda 2 Beijing Rising 1 Guangzhou Development Bank 2 Tencent 3 Back of Beijing 1

address.txt文件內容

addressID addressname 1 Beijing 2 Guangzhou 3 Shenzhen 4 Xian

輸出

factoryname addressname Back of Beijing Beijing Beijing Red Star Beijing Beijing Rising Beijing Guangzhou Development Bank Guangzhou Guangzhou Honda Guangzhou Shenzhen Thunder Shenzhen Tencent Shenzhen

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四、join方法

<W> JavaPairRDD<K, Tuple2<V, W>> join(JavaPairRDD<K, W> other)

關聯表返回相同可以的鍵值對

總結

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