java - 使用 Hadoop 时如何解决 NoClassDefFoundError？

Question

我正进入(状态

Exception in thread "main" java.lang.NoClassDefFoundError: com/linkedin/camus/etl/IEtlKey.

在运行命令时:

hadoop jar camus-etl-kafka-0.1.0-SNAPSHOT.jar 
com.linkedin.camus.etl.kafka.CamusJob -P camus.properties

我得到以下异常(exception)..

2016-04-27 11:34:04.622 java[13567:351959] Unable to load realm mapping info from SCDynamicStore
[NativeCodeLoader] - Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Exception in thread "main" java.lang.NoClassDefFoundError: com/linkedin/camus/etl/IEtlKey
    at com.linkedin.camus.etl.kafka.CamusJob.run(CamusJob.java:252)
    at com.linkedin.camus.etl.kafka.CamusJob.run(CamusJob.java:235)
    at com.linkedin.camus.etl.kafka.CamusJob.run(CamusJob.java:691)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:84)
    at com.linkedin.camus.etl.kafka.CamusJob.main(CamusJob.java:646)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
Caused by: java.lang.ClassNotFoundException: com.linkedin.camus.etl.IEtlKey

我已包含 camus-example-0.1.0-SNAPSHOT-shaded.jar在类路径中。

如果我遗漏了什么，请告诉我。

提前致谢

苏米亚 git

Answer 1

您应该尝试包含 camus-api您可以在此找到 LinkedIn's previous generation Kafka to HDFS pipeline页面，因为缺少的类包含在此包中，如您所见 here .

注意 Camus 可能需要的其他传递依赖。

此外，当您使用 hadoop jar 时，要确保在类路径中可以找到类。从命令行，您可以添加 libjars命令行选项，如 Using the libjars option with Hadoop 中所述:

$ export LIBJARS=/path/jar1,/path/jar2
$ hadoop jar my-example.jar com.example.MyTool -libjars ${LIBJARS} -mytoolopt value

知道加缪将被地精取代可能会很有用:

Camus is being phased out and replaced by Gobblin. For those using or interested in Camus, we suggest taking a look at Gobblin.

For instructions on Migrating from Camus to Gobblin, please take a look at Camus Gobblin Migration.