Question

我正在Spark中使用Jena。在群集上进行部署时，我遇到一个奇怪的问题（在本地Dev上不会发生，因为我不需要构建uber jar）

在群集上部署时，出现以下异常：

Caused by: org.apache.jena.shared.NoReaderForLangException: Reader not found: JSON-LD
 at org.apache.jena.rdf.model.impl.RDFReaderFImpl.getReader(RDFReaderFImpl.java:61)
at org.apache.jena.rdf.model.impl.ModelCom.read(ModelCom.java:305)

1-我想知道，一般来讲，org.apache.jena.shared.NoReaderForLangException: Reader not found: JSON-LD之类的错误可能来自何处？同样，此代码在本地模式下也可以完美地工作。

2-我的Build.sbt组装策略：

lazy val entellectextractorsmappers = project
  .settings(
      commonSettings,
      mainClass in assembly := Some("entellect.extractors.mappers.NormalizedDataMapper"),
      assemblyMergeStrategy in assembly := {
        case "application.conf" => MergeStrategy.concat
        case "reference.conf"   => MergeStrategy.concat
        case PathList("META-INF", "services", "org.apache.jena.system.JenaSubsystemLifecycle") => MergeStrategy.concat
        case PathList("META-INF", "services", "org.apache.spark.sql.sources.DataSourceRegister") => MergeStrategy.concat
        case PathList("META-INF", xs @ _*) => MergeStrategy.discard
        case x => MergeStrategy.first},
      dependencyOverrides += "com.fasterxml.jackson.core" % "jackson-core" % "2.9.5",
      dependencyOverrides += "com.fasterxml.jackson.core" % "jackson-databind" % "2.9.5",
      dependencyOverrides += "com.fasterxml.jackson.module" % "jackson-module-scala_2.11" % "2.9.5",
      dependencyOverrides += "org.apache.jena" % "apache-jena" % "3.8.0",
      libraryDependencies ++= Seq(
      "org.apache.jena" % "apache-jena" % "3.8.0",
      "edu.isi" % "karma-offline" % "0.0.1-SNAPSHOT",
      "org.apache.spark" % "spark-core_2.11" % "2.3.1" % "provided",
      "org.apache.spark" % "spark-sql_2.11" % "2.3.1" % "provided",
      "org.apache.spark" %% "spark-sql-kafka-0-10" % "2.3.1"
      //"com.datastax.cassandra" % "cassandra-driver-core" % "3.5.1"
    ))
  .dependsOn(entellectextractorscommon)

如果有人关于使用Jena和Spark的提示真棒，那么其他任何提示可能导致找不到Reader的提示：JSON-LD，如何时发生，或者从库的角度来看意味着什么。这样，我可以追溯到包装中导致这种情况发生的原因。

Spark org.apache.jena.shared.NoReaderForLangException：未找到阅读器：JSON-LD

0 个答案: