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scala - ClassNotFoundException：引起：java.lang.ClassNotFoundException：csv.DefaultSource

问题描述

我正在尝试创建一个程序集 jar 可执行文件但收到以下错误

Caused by: java.lang.ClassNotFoundException: csv.DefaultSource

问题在于读取的 CSV 文件。代码在 IDE 中运行良好。请帮我

Scala代码如下

package extendedtable

import org.apache.log4j.{Level, Logger}
import org.apache.spark.SparkContext
import org.apache.spark.sql.{DataFrame, Row, SparkSession}
import scala.collection.mutable.ListBuffer

object mainObject {

 // var read = new fileRead
  def main(args: Array[String]): Unit = {
    val spark: SparkSession = SparkSession.builder().appName("generationobj").master("local[*]").config("spark.sql.crossJoin.enabled", value = true).getOrCreate()
    val sc: SparkContext = spark.sparkContext
    import spark.implicits._

    val atomData = spark.read.format("csv")
      .option("header", "true")
      .option("inferSchema", "true")
      .load("Resources/atom.csv")

    val moleculeData = spark.read.format("csv")
      .option("header", "true")
      .option("inferSchema", "true")
      .load("Resources/molecule.csv")

    val df = moleculeData.join(atomData,"molecule_id")
    val molecule_df = moleculeData
    val mid: List[Row] = molecule_df.select("molecule_id").collect.toList
    var listofmoleculeid: List[String] = mid.map(r => r.getString(0))
    // print(listofmoleculeid)
    newDF.createTempView("table")
    newDF.show()}

以下是构建文件 

name := "ExtendedTable"

version := "0.1"

scalaVersion := "2.11.12"

libraryDependencies += "org.apache.spark" %% "spark-core" % "2.3.0"
libraryDependencies += "org.apache.spark" %% "spark-sql" % "2.3.0"
libraryDependencies += "org.apache.spark" %% "spark-mllib" % "2.3.0"

mainClass := Some("extendedtable.mainObject")

assemblyMergeStrategy in assembly := {
  case PathList("META-INF", xs @ _*) => MergeStrategy.discard
  case x => MergeStrategy.first
}

标签： scalaapache-spark

解决方案

在下面更改您的assemblyMergeStrategy喜欢然后构建 jar 文件。

您需要将此org.apache.spark.sql.sources.DataSourceRegister文件包含在您的 jar 文件中，并且此文件将在spark-sqljar 文件中可用。

路径是 -spark-sql_2.11-<version>.jar /META-INF/services/org.apache.spark.sql.sources.DataSourceRegister

此文件包含以下列表

org.apache.spark.sql.execution.datasources.csv.CSVFileFormat
org.apache.spark.sql.execution.datasources.jdbc.JdbcRelationProvider
org.apache.spark.sql.execution.datasources.json.JsonFileFormat
org.apache.spark.sql.execution.datasources.parquet.ParquetFileFormat
org.apache.spark.sql.execution.datasources.text.TextFileFormat
org.apache.spark.sql.execution.streaming.ConsoleSinkProvider
org.apache.spark.sql.execution.streaming.TextSocketSourceProvider
org.apache.spark.sql.execution.streaming.RateSourceProvider

assemblyMergeStrategy in assembly := {
  case PathList("META-INF","services",xs @ _*) => MergeStrategy.filterDistinctLines // Added this 
  case PathList("META-INF",xs @ _*) => MergeStrategy.discard  
  case _ => MergeStrategy.first
}

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