1：练习spark的时候，操作大概如我读取hdfs上面的文件，然后spark懒加载以后，我读取详细信息出现如下所示的错误，错误虽然不大，我感觉有必要记录一下，因为错误的起因是对命令的不熟悉造成的，错误如下所示：
1 scala> text.collect 2 java.net.ConnectException: Call From slaver1/192.168.19.128 to slaver1:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see: http://wiki.apache.org/hadoop/ConnectionRefused 3 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 4 at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) 5 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 6 at java.lang.reflect.Constructor.newInstance(Constructor.java:526) 7 at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:791) 8 at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:731) 9 at org.apache.hadoop.ipc.Client.call(Client.java:1472) 10 at org.apache.hadoop.ipc.Client.call(Client.java:1399) 11 at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:232) 12 at com.sun.proxy.$Proxy36.getFileInfo(Unknown Source) 13 at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getFileInfo(ClientNamenodeProtocolTranslatorPB.java:752) 14 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 15 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 16 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 17 at java.lang.reflect.Method.invoke(Method.java:606) 18 at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:187) 19 at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102) 20 at com.sun.proxy.$Proxy37.getFileInfo(Unknown Source) 21 at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:1988) 22 at org.apache.hadoop.hdfs.DistributedFileSystem$18.doCall(DistributedFileSystem.java:1118) 23 at org.apache.hadoop.hdfs.DistributedFileSystem$18.doCall(DistributedFileSystem.java:1114) 24 at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81) 25 at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1114) 26 at org.apache.hadoop.fs.Globber.getFileStatus(Globber.java:57) 27 at org.apache.hadoop.fs.Globber.glob(Globber.java:252) 28 at org.apache.hadoop.fs.FileSystem.globStatus(FileSystem.java:1644) 29 at org.apache.hadoop.mapred.FileInputFormat.singleThreadedListStatus(FileInputFormat.java:257) 30 at org.apache.hadoop.mapred.FileInputFormat.listStatus(FileInputFormat.java:228) 31 at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:313) 32 at org.apache.spark.rdd.HadoopRDD.getPartitions(HadoopRDD.scala:199) 33 at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) 34 at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) 35 at scala.Option.getOrElse(Option.scala:120) 36 at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) 37 at org.apache.spark.rdd.MapPartitionsRDD.getPartitions(MapPartitionsRDD.scala:35) 38 at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:239) 39 at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:237) 40 at scala.Option.getOrElse(Option.scala:120) 41 at org.apache.spark.rdd.RDD.partitions(RDD.scala:237) 42 at org.apache.spark.SparkContext.runJob(SparkContext.scala:1929) 43 at org.apache.spark.rdd.RDD$$anonfun$collect$1.apply(RDD.scala:927) 44 at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:150) 45 at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:111) 46 at org.apache.spark.rdd.RDD.withScope(RDD.scala:316) 47 at org.apache.spark.rdd.RDD.collect(RDD.scala:926) 48 at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:30) 49 at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:35) 50 at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:37) 51 at $iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:39) 52 at $iwC$$iwC$$iwC$$iwC.<init>(<console>:41) 53 at $iwC$$iwC$$iwC.<init>(<console>:43) 54 at $iwC$$iwC.<init>(<console>:45) 55 at $iwC.<init>(<console>:47) 56 at <init>(<console>:49) 57 at .<init>(<console>:53) 58 at .<clinit>(<console>) 59 at .<init>(<console>:7) 60 at .<clinit>(<console>) 61 at $print(<console>) 62 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 63 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 64 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 65 at java.lang.reflect.Method.invoke(Method.java:606) 66 at org.apache.spark.repl.SparkIMain$ReadEvalPrint.call(SparkIMain.scala:1065) 67 at org.apache.spark.repl.SparkIMain$Request.loadAndRun(SparkIMain.scala:1346) 68 at org.apache.spark.repl.SparkIMain.loadAndRunReq$1(SparkIMain.scala:840) 69 at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:871) 70 at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:819) 71 at org.apache.spark.repl.SparkILoop.reallyInterpret$1(SparkILoop.scala:857) 72 at org.apache.spark.repl.SparkILoop.interpretStartingWith(SparkILoop.scala:902) 73 at org.apache.spark.repl.SparkILoop.command(SparkILoop.scala:814) 74 at org.apache.spark.repl.SparkILoop.processLine$1(SparkILoop.scala:657) 75 at org.apache.spark.repl.SparkILoop.innerLoop$1(SparkILoop.scala:665) 76 at org.apache.spark.repl.SparkILoop.org$apache$spark$repl$SparkILoop$$loop(SparkILoop.scala:670) 77 at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply$mcZ$sp(SparkILoop.scala:997) 78 at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply(SparkILoop.scala:945) 79 at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply(SparkILoop.scala:945) 80 at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135) 81 at org.apache.spark.repl.SparkILoop.org$apache$spark$repl$SparkILoop$$process(SparkILoop.scala:945) 82 at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:1059) 83 at org.apache.spark.repl.Main$.main(Main.scala:31) 84 at org.apache.spark.repl.Main.main(Main.scala) 85 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 86 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 87 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 88 at java.lang.reflect.Method.invoke(Method.java:606) 89 at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:731) 90 at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:181) 91 at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:206) 92 at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:121) 93 at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala) 94 Caused by: java.net.ConnectException: Connection refused 95 at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) 96 at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:739) 97 at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206) 98 at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:530) 99 at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:494) 100 at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:607) 101 at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:705) 102 at org.apache.hadoop.ipc.Client$Connection.access$2800(Client.java:368) 103 at org.apache.hadoop.ipc.Client.getConnection(Client.java:1521) 104 at org.apache.hadoop.ipc.Client.call(Client.java:1438) 105 ... 84 more
2：错误原因如下所示：
我使用了如下所示命令来读取hdfs上面的文件，scala> var text = sc.textFile("hdfs://slaver1:/input.txt");，然后使用text.collect命令来查看详细信息，就是查看详细信息的时候报的上面的错误，错误原因是因为我读取hdfs文件的时候少了端口号，造成的错误；
修改为如下所示即可：
scala> var text = sc.textFile("hdfs://slaver1:9000/input.txt"); scala> text.collect