问题：java.net.ConnectException: Call From Master/xxx.xxx.x.xxx to user:8020 failed on connection exception: java.net.ConnectException: Connection refused

scala> disfile.collect().foreach(println)
java.net.ConnectException: Call From Master/xxx.xxx.x.xxx to user:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
  at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
  at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
  at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
  at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
  at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:792)
  at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:732)
  at org.apache.hadoop.ipc.Client.call(Client.java:1479)
  at org.apache.hadoop.ipc.Client.call(Client.java:1412)
  at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:229)
  at com.sun.proxy.$Proxy59.getFileInfo(Unknown Source)
  at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getFileInfo(ClientNamenodeProtocolTranslatorPB.java:771)
  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 org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:191)
  at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
  at com.sun.proxy.$Proxy60.getFileInfo(Unknown Source)
  at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:2108)
  at org.apache.hadoop.hdfs.DistributedFileSystem$22.doCall(DistributedFileSystem.java:1305)
  at org.apache.hadoop.hdfs.DistributedFileSystem$22.doCall(DistributedFileSystem.java:1301)
  at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
  at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1317)
  at org.apache.hadoop.fs.Globber.getFileStatus(Globber.java:57)
  at org.apache.hadoop.fs.Globber.glob(Globber.java:252)
  at org.apache.hadoop.fs.FileSystem.globStatus(FileSystem.java:1674)
  at org.apache.hadoop.mapred.FileInputFormat.singleThreadedListStatus(FileInputFormat.java:259)
  at org.apache.hadoop.mapred.FileInputFormat.listStatus(FileInputFormat.java:229)
  at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:315)
  at org.apache.spark.rdd.HadoopRDD.getPartitions(HadoopRDD.scala:194)
  at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:252)
  at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:250)
  at scala.Option.getOrElse(Option.scala:121)
  at org.apache.spark.rdd.RDD.partitions(RDD.scala:250)
  at org.apache.spark.rdd.MapPartitionsRDD.getPartitions(MapPartitionsRDD.scala:35)
  at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:252)
  at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:250)
  at scala.Option.getOrElse(Option.scala:121)
  at org.apache.spark.rdd.RDD.partitions(RDD.scala:250)
  at org.apache.spark.SparkContext.runJob(SparkContext.scala:2087)
  at org.apache.spark.rdd.RDD$$anonfun$collect$1.apply(RDD.scala:936)
  at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:151)
  at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:112)
  at org.apache.spark.rdd.RDD.withScope(RDD.scala:362)
  at org.apache.spark.rdd.RDD.collect(RDD.scala:935)
  ... 48 elided
Caused by: java.net.ConnectException: Connection refused
  at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
  at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
  at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
  at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:531)
  at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:495)
  at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:614)
  at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:712)
  at org.apache.hadoop.ipc.Client$Connection.access$2900(Client.java:375)
  at org.apache.hadoop.ipc.Client.getConnection(Client.java:1528)
  at org.apache.hadoop.ipc.Client.call(Client.java:1451)
  ... 86 more

问题原因：读取HDFS文件时，代码写的是相对路径，Spark 默认的 hdfs 端口号为 8020，而在配置hadoop的core-site.xml文件时，将其端口设置成为 9000

解决方法：读取HDFS文件时，写成绝对路径

scala> val disfile =sc.textFile("hdfs://Master:9000/user/hive/warehouse/emp_test1/emp_test1.txt")
disfile: org.apache.spark.rdd.RDD[String] = hdfs://Master:9000/user/hive/warehouse/emp_test1/emp_test1.txt MapPartitionsRDD[14] at textFile at <console>:24

scala> disfile.collect().foreach(println)
[Stage 1:>                                                          (0 + 0) / 2[Stage 1:>                                                          (0 + 1) / 2manage  1       zs      manger  5                                               
saleman	2	ls	saleman	3