toDF不通过导入sqlContext.implicits._进行编译 [英] toDF does not compile though import sqlContext.implicits._ is used
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问题描述
当我想使用 toDF 为了将RDD传递给DataFrame时，我有一些编译Spark Scala代码的问题。我检查了Spark 2.0.0和1.6.2，问题是一直的。
下面我提供了我的POM文件和代码：
I have some issue with compiling the Spark Scala code when I want to use toDF in order to pass RDD to DataFrame. I checked both Spark 2.0.0 and 1.6.2, and the problem is the same all the time.
Below I provide my POM file and the piece of code:
POM.xml
<?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>org.test</groupId>
<artifactId>test_service</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<scala.version>2.10.6</scala.version>
<spark.version>2.0.0</spark.version>
<jackson.version>2.8.3</jackson.version>
</properties>
<dependencies>
<dependency>
<groupId>org.scala-lang</groupId>
<artifactId>scala-library</artifactId>
<version>${scala.version}</version>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-streaming-kafka_2.10</artifactId>
<version>1.6.2</version>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-sql_2.10</artifactId>
<version>${spark.version}</version>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-core_2.10</artifactId>
<version>${spark.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-streaming_2.10</artifactId>
<version>${spark.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-mllib_2.10</artifactId>
<version>${spark.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.module</groupId>
<artifactId>jackson-module-scala_2.10</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.module</groupId>
<artifactId>jackson-module-scala_2.10</artifactId>
<version>2.8.3</version>
</dependency>
<dependency>
<groupId>org.sedis</groupId>
<artifactId>sedis_2.10</artifactId>
<version>1.2.2</version>
</dependency>
<dependency>
<groupId>com.lambdaworks</groupId>
<artifactId>jacks_2.10</artifactId>
<version>2.3.3</version>
</dependency>
<dependency>
<groupId>com.github.nscala-time</groupId>
<artifactId>nscala-time_2.10</artifactId>
<version>2.12.0</version>
</dependency>
<dependency>
<groupId>com.typesafe</groupId>
<artifactId>config</artifactId>
<version>1.3.1</version>
</dependency>
<dependency>
<groupId>com.amazonaws</groupId>
<artifactId>aws-java-sdk-s3</artifactId>
<version>1.11.53</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<id>build-a</id>
<configuration>
<archive>
<manifest>
<mainClass>org.test.Runner1</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<finalName>runner1</finalName>
</configuration>
<phase>package</phase>
<goals>
<goal>assembly</goal>
</goals>
</execution>
<execution>
<id>build-b</id>
<configuration>
<archive>
<manifest>
<mainClass>org.test.Runner2</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<finalName>runner2</finalName>
</configuration>
<phase>package</phase>
<goals>
<goal>assembly</goal>
</goals>
</execution>
</executions>
</plugin>
<!-- Configure maven-compiler-plugin to use the desired Java version -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
<!-- Use build-helper-maven-plugin to add Scala source and test source directories -->
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<version>1.10</version>
<executions>
<execution>
<id>add-source</id>
<phase>generate-sources</phase>
<goals>
<goal>add-source</goal>
</goals>
<configuration>
<sources>
<source>src/main/scala</source>
</sources>
</configuration>
</execution>
<execution>
<id>add-test-source</id>
<phase>generate-test-sources</phase>
<goals>
<goal>add-test-source</goal>
</goals>
<configuration>
<sources>
<source>src/test/scala</source>
</sources>
</configuration>
</execution>
</executions>
</plugin>
<!-- Use scala-maven-plugin for Scala support -->
<plugin>
<groupId>net.alchim31.maven</groupId>
<artifactId>scala-maven-plugin</artifactId>
<version>3.2.2</version>
<executions>
<execution>
<goals>
<!-- Need to specify this explicitly, otherwise plugin won't be called when doing e.g. mvn compile -->
<goal>compile</goal>
<goal>testCompile</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
提供错误的代码片段（rdd - > RDD [Map [ String，Any]] ）：
Piece of code that provides an error (rdd -> RDD[Map[String,Any]]):
import org.apache.spark.sql.SQLContext
import org.apache.spark.streaming.kafka.KafkaUtils
import org.apache.spark.streaming.{Seconds, StreamingContext}
import org.apache.spark.{SparkConf, SparkContext}
val sqlContext = new org.apache.spark.sql.SQLContext(sc)
import sqlContext.implicits._
myDStream.foreachRDD { rdd =>
val features = rdd.map(line => line.keySet).first().toList
val myDF = filtered.toDF(features: _*) // toDF is not recognized!!!
}
推荐答案
预期。 RDD [Map [String，Any]] 无法转换为 DataFrame ：
- 没有隐式转换 https://spark.apache.org/docs/1.6.0/api/scala/index.html#org.apache.spark.sql.SQLContext $ implicits $
-
DataFrame不支持任何li>
- there is no implicit conversion https://spark.apache.org/docs/1.6.0/api/scala/index.html#org.apache.spark.sql.SQLContext$implicits$
DataFramedoesn't supportAny.
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