报错如下： 

Error:scalac: Error: bad symbolic reference. A signature in SparkContext.class refers to term conf
in package org.apache.hadoop which is not available.
It may be completely missing from the current classpath, or the version on
the classpath might be incompatible with the version used when compiling SparkContext.class.
scala.reflect.internal.Types$TypeError: bad symbolic reference. A signature in SparkContext.class refers to term conf
in package org.apache.hadoop which is not available.
It may be completely missing from the current classpath, or the version on
the classpath might be incompatible with the version used when compiling SparkContext.class.at scala.reflect.internal.pickling.UnPickler$Scan.toTypeError(UnPickler.scala:847)at scala.reflect.internal.pickling.UnPickler$Scan$LazyTypeRef.complete(UnPickler.scala:854)at scala.reflect.internal.pickling.UnPickler$Scan$LazyTypeRef.load(UnPickler.scala:863)at scala.reflect.internal.Symbols$Symbol.typeParams(Symbols.scala:1489)at scala.tools.nsc.transform.SpecializeTypes$$anonfun$scala$tools$nsc$transform$SpecializeTypes$$normalizeMember$1.apply(SpecializeTypes.scala:798)at scala.tools.nsc.transform.SpecializeTypes$$anonfun$scala$tools$nsc$transform$SpecializeTypes$$normalizeMember$1.apply(SpecializeTypes.scala:798)at scala.reflect.internal.SymbolTable.atPhase(SymbolTable.scala:207)at scala.reflect.internal.SymbolTable.beforePhase(SymbolTable.scala:215)at scala.tools.nsc.transform.SpecializeTypes.scala$tools$nsc$transform$SpecializeTypes$$normalizeMember(SpecializeTypes.scala:797)at scala.tools.nsc.transform.SpecializeTypes$$anonfun$22.apply(SpecializeTypes.scala:751)at scala.tools.nsc.transform.SpecializeTypes$$anonfun$22.apply(SpecializeTypes.scala:749)at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:251)at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:251)at scala.collection.immutable.List.foreach(List.scala:318)at scala.collection.TraversableLike$class.flatMap(TraversableLike.scala:251)at scala.collection.AbstractTraversable.flatMap(Traversable.scala:105)at scala.tools.nsc.transform.SpecializeTypes.specializeClass(SpecializeTypes.scala:749)at scala.tools.nsc.transform.SpecializeTypes.transformInfo(SpecializeTypes.scala:1172)at scala.tools.nsc.transform.InfoTransform$Phase$$anon$1.transform(InfoTransform.scala:38)at scala.reflect.internal.Symbols$Symbol.rawInfo(Symbols.scala:1321)at scala.reflect.internal.Symbols$Symbol.info(Symbols.scala:1241)at scala.reflect.internal.Symbols$Symbol.isDerivedValueClass(Symbols.scala:658)at scala.reflect.internal.transform.Erasure$ErasureMap.apply(Erasure.scala:131)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1283)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)at scala.reflect.internal.Trees$$anonfun$itransform$1.apply(Trees.scala:1229)at scala.reflect.internal.Trees$$anonfun$itransform$1.apply(Trees.scala:1228)at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:28)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:19)at scala.reflect.internal.Trees$class.itransform(Trees.scala:1227)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:48)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)at scala.reflect.api.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:2927)at scala.reflect.api.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:2925)at scala.collection.immutable.List.loop$1(List.scala:170)at scala.collection.immutable.List.mapConserve(List.scala:186)at scala.reflect.api.Trees$Transformer.transformStats(Trees.scala:2925)at scala.reflect.internal.Trees$class.itransform(Trees.scala:1238)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:48)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)at scala.reflect.internal.Trees$$anonfun$itransform$2.apply(Trees.scala:1235)at scala.reflect.internal.Trees$$anonfun$itransform$2.apply(Trees.scala:1233)at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:28)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:19)at scala.reflect.internal.Trees$class.itransform(Trees.scala:1232)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:48)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1288)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)at scala.reflect.api.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:2927)at scala.reflect.api.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:2925)at scala.collection.immutable.List.loop$1(List.scala:170)at scala.collection.immutable.List.mapConserve(List.scala:186)at scala.reflect.api.Trees$Transformer.transformStats(Trees.scala:2925)at scala.reflect.internal.Trees$class.itransform(Trees.scala:1276)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.scala$tools$nsc$transform$TypingTransformers$TypingTransformer$$super$transform(TypingTransformers.scala:44)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer$$anonfun$transform$1.apply(TypingTransformers.scala:44)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer$$anonfun$transform$1.apply(TypingTransformers.scala:44)at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:44)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)at scala.reflect.api.Trees$Transformer.transformTemplate(Trees.scala:2904)at scala.reflect.internal.Trees$$anonfun$itransform$4.apply(Trees.scala:1280)at scala.reflect.internal.Trees$$anonfun$itransform$4.apply(Trees.scala:1279)at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:28)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:19)at scala.reflect.internal.Trees$class.itransform(Trees.scala:1278)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:48)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)at scala.reflect.api.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:2927)at scala.reflect.api.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:2925)at scala.collection.immutable.List.loop$1(List.scala:170)at scala.collection.immutable.List.mapConserve(List.scala:186)at scala.reflect.api.Trees$Transformer.transformStats(Trees.scala:2925)at scala.reflect.internal.Trees$$anonfun$itransform$7.apply(Trees.scala:1298)at scala.reflect.internal.Trees$$anonfun$itransform$7.apply(Trees.scala:1298)at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:28)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:19)at scala.reflect.internal.Trees$class.itransform(Trees.scala:1297)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.scala$tools$nsc$transform$TypingTransformers$TypingTransformer$$super$transform(TypingTransformers.scala:44)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer$$anonfun$transform$2.apply(TypingTransformers.scala:46)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer$$anonfun$transform$2.apply(TypingTransformers.scala:46)at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:46)at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)at scala.tools.nsc.transform.Erasure$ErasureTransformer.transform(Erasure.scala:1302)at scala.tools.nsc.transform.Erasure$ErasureTransformer.transform(Erasure.scala:888)at scala.tools.nsc.ast.Trees$Transformer.transformUnit(Trees.scala:227)at scala.tools.nsc.transform.Transform$Phase.apply(Transform.scala:30)at scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.scala:464)at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:431)at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:431)at scala.collection.Iterator$class.foreach(Iterator.scala:727)at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)at scala.tools.nsc.Global$GlobalPhase.run(Global.scala:431)at scala.tools.nsc.Global$Run.compileUnitsInternal(Global.scala:1583)at scala.tools.nsc.Global$Run.compileUnits(Global.scala:1557)at scala.tools.nsc.Global$Run.compileSources(Global.scala:1553)at scala.tools.nsc.Global$Run.compile(Global.scala:1662)at xsbt.CachedCompiler0.run(CompilerInterface.scala:115)at xsbt.CachedCompiler0.run(CompilerInterface.scala:94)at xsbt.CompilerInterface.run(CompilerInterface.scala:22)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at sbt.compiler.AnalyzingCompiler.call(AnalyzingCompiler.scala:101)at sbt.compiler.AnalyzingCompiler.compile(AnalyzingCompiler.scala:47)at sbt.compiler.AnalyzingCompiler.compile(AnalyzingCompiler.scala:41)at org.jetbrains.jps.incremental.scala.local.IdeaIncrementalCompiler.compile(IdeaIncrementalCompiler.scala:32)at org.jetbrains.jps.incremental.scala.local.LocalServer.compile(LocalServer.scala:26)at org.jetbrains.jps.incremental.scala.remote.Main$.make(Main.scala:68)at org.jetbrains.jps.incremental.scala.remote.Main$.nailMain(Main.scala:25)at org.jetbrains.jps.incremental.scala.remote.Main.nailMain(Main.scala)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at com.martiansoftware.nailgun.NGSession.run(NGSession.java:319)

问题原因：少引入了hadoop-client包

pom.xml中加入

   <dependency><groupId>org.apache.hadoop</groupId><artifactId>hadoop-client</artifactId><version>2.6.0</version></dependency>