PigUnit與Hadoop 2.x

Question

我正在嘗試將PigUnit與Hadoop 2.4.1一起使用。 我有一個非常簡單的Pig腳本，我想在PigTest中執行，但是當我運行這個測試時，我得到以下異常：

java.lang.InstantiationError: org.apache.hadoop.mapreduce.JobContext
    at org.apache.pig.backend.hadoop.executionengine.shims.HadoopShims.createJobContext(HadoopShims.java:66)
    at org.apache.pig.backend.hadoop.executionengine.fetch.FetchPOStoreImpl.createStoreFunc(FetchPOStoreImpl.java:58)
    at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POStore.setUp(POStore.java:103)
    at org.apache.pig.backend.hadoop.executionengine.fetch.FetchLauncher.init(FetchLauncher.java:121)
    at org.apache.pig.backend.hadoop.executionengine.fetch.FetchLauncher.launchPig(FetchLauncher.java:78)
    at org.apache.pig.backend.hadoop.executionengine.HExecutionEngine.launchPig(HExecutionEngine.java:275)
    at org.apache.pig.PigServer.launchPlan(PigServer.java:1367)
    at org.apache.pig.PigServer.executeCompiledLogicalPlan(PigServer.java:1352)
    at org.apache.pig.PigServer.storeEx(PigServer.java:1011)
    at org.apache.pig.PigServer.store(PigServer.java:974)
    at org.apache.pig.PigServer.openIterator(PigServer.java:887)
    at org.apache.pig.tools.grunt.GruntParser.processDump(GruntParser.java:752)
    at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:372)
    at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:228)
    at org.apache.pig.pigunit.pig.PigServer.registerScript(PigServer.java:55)
    at org.apache.pig.pigunit.PigTest.registerScript(PigTest.java:170)
    at org.apache.pig.pigunit.PigTest.assertOutput(PigTest.java:242)
    at com.mongodb.hadoop.pig.PigTest.testSimplePigScript(PigTest.java:57)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:74)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:211)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:67)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)

在Hadoop 2.4.1中，org.apache.hadoop.mapreduce.JobContext是一個接口，而不是一個類，所以在我看來，像PigUnit在某種程度上期待一個舊版本的Hadoop？ 如果確實如此，我如何將PigUnit指向更新的Hadoop罐子？

Answer 1

事實證明，我使用了錯誤的豬的verison。 Pig在Maven上有多個工件，我需要在build.gradle中提供一個分類build.gradle ，以便指定適用於Hadoop 2.x的Pig jar：

compile "org.apache.pig:pig:${pigVersion}:h2"

這篇文章幫助我解決了Gradle /依賴問題。