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java - 提交 Flink 作业时出现 java.lang.NoClassDefFoundError

问题描述

我正在尝试通过在命令行中运行来提交使用 Scala 2.11 创建的 Flink 作业，该作业使用本地 Flink 集群中的 Twitter 流 API：

flink run -c org.myClass C:\path\to\jarFile.jar

并得到以下错误：

2019-06-09 23:40:47,758 WARN  org.apache.flink.runtime.webmonitor.handlers.JarRunHandler    - Configuring the job submission via query parameters is deprecated. Please migrate to submitting a JSON request instead.
2019-06-09 23:40:47,762 ERROR org.apache.flink.runtime.webmonitor.handlers.JarRunHandler    - Unhandled exception.
org.apache.flink.client.program.ProgramInvocationException: The program caused an error: 
    at org.apache.flink.client.program.OptimizerPlanEnvironment.getOptimizedPlan(OptimizerPlanEnvironment.java:93)
    at org.apache.flink.client.program.PackagedProgramUtils.createJobGraph(PackagedProgramUtils.java:80)
    at org.apache.flink.runtime.webmonitor.handlers.utils.JarHandlerUtils$JarHandlerContext.toJobGraph(JarHandlerUtils.java:126)
    at org.apache.flink.runtime.webmonitor.handlers.JarRunHandler.lambda$getJobGraphAsync$6(JarRunHandler.java:142)
    at java.util.concurrent.CompletableFuture$AsyncSupply.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NoClassDefFoundError: org/apache/flink/streaming/connectors/twitter/TwitterSource$EndpointInitializer
    at msciss.TwitterHashtagCounter.main(TwitterHashtagCounter.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:529)
    at org.apache.flink.client.program.PackagedProgram.invokeInteractiveModeForExecution(PackagedProgram.java:421)
    at org.apache.flink.client.program.OptimizerPlanEnvironment.getOptimizedPlan(OptimizerPlanEnvironment.java:83)
    ... 7 more
Caused by: java.lang.ClassNotFoundException: org.apache.flink.streaming.connectors.twitter.TwitterSource$EndpointInitializer
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 15 more

但是在程序中，我在下面的 build.sbt 中设置了 TwitterSource 库：

val flinkDependencies = Seq(
  "org.apache.flink" %% "flink-scala" % flinkVersion % "provided",
  "org.apache.flink" %% "flink-streaming-scala" % flinkVersion % "provided",
  "org.apache.flink" %% "flink-connector-twitter" % flinkVersion,
  "commons-logging" % "commons-logging" % "1.2",
  "org.apache.logging.log4j" % "log4j-core" % "2.11.2",
  "org.apache.commons" % "commons-text" % "1.6")

该应用程序在 IntelliJ 中也可以正常运行，并且 sbt buld / package 不会产生任何问题。我该如何解决这个问题？

标签： javascalasbtapache-flinkflink-streaming

解决方案

您需要使用sbt assembly插件或任何其他允许创建 Fat Jar (Uber Jar) 的插件。目前，您的包不包含外部库，并且 flink 连接器被视为外部库，因为它们不包含在标准二进制构建中。因此，您实际上正在创建您正在创建的包不包含twitter-connector，但 Flink 本身也不包含，这就是您获得ClassNotFoundException.

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