如何使用Scala在Spark中创建SQLContext？

Question

我正在创建一个SQLContext使用sbt 的Scala程序。这是我的build.sbt：

name := "sampleScalaProject"

version := "1.0"

scalaVersion := "2.11.7"
//libraryDependencies += "org.apache.spark" %% "spark-core" % "2.5.2"
libraryDependencies += "org.apache.spark" % "spark-core_2.11" % "1.5.2"
libraryDependencies += "org.apache.kafka" % "kafka_2.11" % "0.8.2.2"
libraryDependencies += "org.apache.spark" % "spark-streaming_2.11" % "1.5.2"
libraryDependencies += "org.apache.spark" % "spark-sql_2.11" % "1.5.2"
libraryDependencies += "org.apache.hadoop" % "hadoop-common" % "2.6.0"  

这是测试程序：

import org.apache.spark.SparkContext
import org.apache.spark.sql.SQLContext

object SqlContextSparkScala {

  def main (args: Array[String]) {
    val sc = SparkContext
    val sqlcontext = new SQLContext(sc)
  }
} 

我得到以下错误：

Error:(8, 26) overloaded method constructor SQLContext with alternatives:
  (sparkContext: org.apache.spark.api.java.JavaSparkContext)org.apache.spark.sql.SQLContext <and>
  (sparkContext: org.apache.spark.SparkContext)org.apache.spark.sql.SQLContext
 cannot be applied to (org.apache.spark.SparkContext.type)
    val sqlcontexttest = new SQLContext(sc)  

谁能让我知道这个问题，因为我是scala和spark编程的新手？

Answer 1

对于较新版本的 Spark (2.0+)，请使用SparkSession：

val spark = SparkSession.builder.getOrCreate()

SparkSession可以做所有SQLContext可以做的事情，但如果需要，SQLContext可以按如下方式访问，

val sqlContext = spark.sqlContext

Answer 2

您需要new您的SparkContext，那应该解决它