不兼容的Jackson版本：Spark结构化流

我正在尝试运行一个非常简单的Spark Streaming字数统计程序，该程序从一个Kafka主题读取。下面是我的代码：

val spark = SparkSession
  .builder()
  .appName("KafkaWordCount")
  .config("spark.master", "local")
  .getOrCreate()

import spark.implicits._

val df = spark
  .readStream
  .format("kafka")
  .option("kafka.bootstrap.servers", "localhost:9092")
  .option("subscribe", "test")
  .load()

val lines = df.selectExpr("CAST(value AS STRING)").as[String]

val words = lines.flatMap(_.split(" "))

val wordCounts = words.groupBy("value").count()

val query = wordCounts.writeStream
  .outputMode("complete")
  .format("console")
  .start()

query.awaitTermination()

运行该程序时，出现以下异常：

Exception in thread "stream execution thread for [id = f704d6e5-14bf-4bd7-94a0-38c4b77986ea, runId = d277eaac-e18c-4128-954b-6a318bb8039c]" Exception in thread "main" java.lang.ExceptionInInitializerError
    at org.apache.spark.rdd.RDD.withScope(RDD.scala:363)
    at org.apache.spark.rdd.RDD.map(RDD.scala:370)
    at org.apache.spark.sql.kafka010.KafkaSource.getBatch(KafkaSource.scala:287)
    at org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$org$apache$spark$sql$execution$streaming$MicroBatchExecution$$runBatch$1$$anonfun$apply$9.apply(MicroBatchExecution.scala:394)
    at org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$org$apache$spark$sql$execution$streaming$MicroBatchExecution$$runBatch$1$$anonfun$apply$9.apply(MicroBatchExecution.scala:390)
    at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:241)
    at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:241)
    at scala.collection.Iterator$class.foreach(Iterator.scala:893)
    at scala.collection.AbstractIterator.foreach(Iterator.scala:1336)
    at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)
    at org.apache.spark.sql.execution.streaming.StreamProgress.foreach(StreamProgress.scala:25)
    at scala.collection.TraversableLike$class.flatMap(TraversableLike.scala:241)
    at org.apache.spark.sql.execution.streaming.StreamProgress.flatMap(StreamProgress.scala:25)
    at org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$org$apache$spark$sql$execution$streaming$MicroBatchExecution$$runBatch$1.apply(MicroBatchExecution.scala:390)
    at org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$org$apache$spark$sql$execution$streaming$MicroBatchExecution$$runBatch$1.apply(MicroBatchExecution.scala:390)
    at org.apache.spark.sql.execution.streaming.ProgressReporter$class.reportTimeTaken(ProgressReporter.scala:271)
    at org.apache.spark.sql.execution.streaming.StreamExecution.reportTimeTaken(StreamExecution.scala:58)
    at org.apache.spark.sql.execution.streaming.MicroBatchExecution.org$apache$spark$sql$execution$streaming$MicroBatchExecution$$runBatch(MicroBatchExecution.scala:389)
    at org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$runActivatedStream$1$$anonfun$apply$mcZ$sp$1.apply$mcV$sp(MicroBatchExecution.scala:133)
    at org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$runActivatedStream$1$$anonfun$apply$mcZ$sp$1.apply(MicroBatchExecution.scala:121)
    at org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$runActivatedStream$1$$anonfun$apply$mcZ$sp$1.apply(MicroBatchExecution.scala:121)
    at org.apache.spark.sql.execution.streaming.ProgressReporter$class.reportTimeTaken(ProgressReporter.scala:271)
    at org.apache.spark.sql.execution.streaming.StreamExecution.reportTimeTaken(StreamExecution.scala:58)
    at org.apache.spark.sql.execution.streaming.MicroBatchExecution$$anonfun$runActivatedStream$1.apply$mcZ$sp(MicroBatchExecution.scala:121)
    at org.apache.spark.sql.execution.streaming.ProcessingTimeExecutor.execute(TriggerExecutor.scala:56)
    at org.apache.spark.sql.execution.streaming.MicroBatchExecution.runActivatedStream(MicroBatchExecution.scala:117)
    at org.apache.spark.sql.execution.streaming.StreamExecution.org$apache$spark$sql$execution$streaming$StreamExecution$$runStream(StreamExecution.scala:279)
    at org.apache.spark.sql.execution.streaming.StreamExecution$$anon$1.run(StreamExecution.scala:189)
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Incompatible Jackson version: 2.9.4
    at com.fasterxml.jackson.module.scala.JacksonModule$class.setupModule(JacksonModule.scala:64)
    at com.fasterxml.jackson.module.scala.DefaultScalaModule.setupModule(DefaultScalaModule.scala:19)
    at com.fasterxml.jackson.databind.ObjectMapper.registerModule(ObjectMapper.java:751)
    at org.apache.spark.rdd.RDDOperationScope$.(RDDOperationScope.scala:82)
    at org.apache.spark.rdd.RDDOperationScope$.(RDDOperationScope.scala)
    ... 28 more
org.apache.spark.sql.streaming.StreamingQueryException: null

其他Stack Overflow答案建议在pom中包含不同版本的jackson。因此，首先这不是专家，而是sbt项目。下面是我的build.sbt

name := "spark"

version := "0.1"

scalaVersion := "2.11.8"

libraryDependencies ++= Seq(
  "org.apache.spark" %% "spark-sql" % "2.3.1",
  "org.apache.spark" %% "spark-sql-kafka-0-10" % "2.3.1",
  "org.apache.kafka" %% "kafka" % "1.1.0"
)

我需要怎么做才能消除此错误并使该程序正常工作？

Apache Spark使用杰克逊2.6.7版本：

2.6.7
2.6.7.1

请参阅Spark项目pom.xml

卡夫卡则使用Jackson Jackson ：“ 2.9.6”版本。

versions += [
  activation: "1.1.1",
  apacheda: "1.0.0",
  apacheds: "2.0.0-M24",
  argparse4j: "0.7.0",
  bcpkix: "1.59",
  easymock: "3.6",
  jackson: "2.9.6",
  jetty: "9.2.24.v20180105",

卡夫卡摇篮

要更正此问题，请覆盖冲突的jar版本，如下所示：

dependencyOverrides += "com.fasterxml.jackson.core" % "jackson-databind" % "2.6.7"

请参考此链接以获取更多详细信息：

https://www.scala-sbt.org/1.x/docs/Library-Management.html#Overriding+a+version