exception: java.net.ConnectException: Connection refused; For more details see: http://wiki.apache.org/hadoop/ConnectionRefused

1、虽然，不是大错，还说要贴一下，由于我运行run-example streaming.NetworkWordCount localhost 9999的测试案例，出现的错误，第一感觉就是Spark没有启动导致的：

 // :: ERROR SparkContext: Error initializing SparkContext.
 java.net.ConnectException: Call From slaver1/192.168.19.131 to slaver1: 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:)
     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:)
     at java.lang.reflect.Constructor.newInstance(Constructor.java:)
     at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:)
     at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:)
     at org.apache.hadoop.ipc.Client.call(Client.java:)
     at org.apache.hadoop.ipc.Client.call(Client.java:)
     at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:)
     at com.sun.proxy.$Proxy12.getFileInfo(Unknown Source)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:)
     at java.lang.reflect.Method.invoke(Method.java:)
     at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:)
     at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:)
     at com.sun.proxy.$Proxy12.getFileInfo(Unknown Source)
     at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getFileInfo(ClientNamenodeProtocolTranslatorPB.java:)
     at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:)
     at org.apache.hadoop.hdfs.DistributedFileSystem$.doCall(DistributedFileSystem.java:)
     at org.apache.hadoop.hdfs.DistributedFileSystem$.doCall(DistributedFileSystem.java:)
     at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:)
     at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:)
     at org.apache.spark.scheduler.EventLoggingListener.start(EventLoggingListener.scala:)
     at org.apache.spark.SparkContext.<init>(SparkContext.scala:)
     at org.apache.spark.streaming.StreamingContext$.createNewSparkContext(StreamingContext.scala:)
     at org.apache.spark.streaming.StreamingContext.<init>(StreamingContext.scala:)
     at org.apache.spark.examples.streaming.NetworkWordCount$.main(NetworkWordCount.scala:)
     at org.apache.spark.examples.streaming.NetworkWordCount.main(NetworkWordCount.scala)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:)
     at java.lang.reflect.Method.invoke(Method.java:)
     at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:)
     at org.apache.spark.deploy.SparkSubmit$.doRunMain$(SparkSubmit.scala:)
     at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:)
     at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:)
     at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
 Caused by: java.net.ConnectException: Connection refused
     at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
     at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:)
     at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:)
     at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:)
     at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:)
     at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:)
     at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:)
     at org.apache.hadoop.ipc.Client$Connection.access$(Client.java:)
     at org.apache.hadoop.ipc.Client.getConnection(Client.java:)
     at org.apache.hadoop.ipc.Client.call(Client.java:)
     ...  more
 // :: INFO SparkUI: Stopped Spark web UI at http://192.168.19.131:4040
 // :: INFO DAGScheduler: Stopping DAGScheduler
 // :: INFO MapOutputTrackerMasterEndpoint: MapOutputTrackerMasterEndpoint stopped!
 // :: INFO MemoryStore: MemoryStore cleared
 // :: INFO BlockManager: BlockManager stopped
 // :: INFO BlockManagerMaster: BlockManagerMaster stopped
 // :: INFO SparkContext: Successfully stopped SparkContext
 Exception in thread "main" java.net.ConnectException: Call From slaver1/192.168.19.131 to slaver1: 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:)
     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:)
     at java.lang.reflect.Constructor.newInstance(Constructor.java:)
     at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:)
     at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:)
     at org.apache.hadoop.ipc.Client.call(Client.java:)
     at org.apache.hadoop.ipc.Client.call(Client.java:)
     at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:)
     at com.sun.proxy.$Proxy12.getFileInfo(Unknown Source)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:)
     at java.lang.reflect.Method.invoke(Method.java:)
     at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:)
     at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:)
     at com.sun.proxy.$Proxy12.getFileInfo(Unknown Source)
     at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getFileInfo(ClientNamenodeProtocolTranslatorPB.java:)
     at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:)
     at org.apache.hadoop.hdfs.DistributedFileSystem$.doCall(DistributedFileSystem.java:)
     at org.apache.hadoop.hdfs.DistributedFileSystem$.doCall(DistributedFileSystem.java:)
     at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:)
     at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:)
     at org.apache.spark.scheduler.EventLoggingListener.start(EventLoggingListener.scala:)
     at org.apache.spark.SparkContext.<init>(SparkContext.scala:)
     at org.apache.spark.streaming.StreamingContext$.createNewSparkContext(StreamingContext.scala:)
     at org.apache.spark.streaming.StreamingContext.<init>(StreamingContext.scala:)
     at org.apache.spark.examples.streaming.NetworkWordCount$.main(NetworkWordCount.scala:)
     at org.apache.spark.examples.streaming.NetworkWordCount.main(NetworkWordCount.scala)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:)
     at java.lang.reflect.Method.invoke(Method.java:)
     at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:)
     at org.apache.spark.deploy.SparkSubmit$.doRunMain$(SparkSubmit.scala:)
     at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:)
     at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:)
     at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
 Caused by: java.net.ConnectException: Connection refused
     at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
     at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:)
     at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:)
     at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:)
     at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:)
     at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:)
     at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:)
     at org.apache.hadoop.ipc.Client$Connection.access$(Client.java:)
     at org.apache.hadoop.ipc.Client.getConnection(Client.java:)
     at org.apache.hadoop.ipc.Client.call(Client.java:)
     ...  more
 // :: INFO OutputCommitCoordinator$OutputCommitCoordinatorEndpoint: OutputCommitCoordinator stopped!
 // :: INFO RemoteActorRefProvider$RemotingTerminator: Shutting down remote daemon.
 // :: INFO ShutdownHookManager: Shutdown hook called
 // :: INFO ShutdownHookManager: Deleting directory /tmp/spark-7ef5c2da-0b57--a9f9-6e215885c7ba
 // :: INFO RemoteActorRefProvider$RemotingTerminator: Remote daemon shut down; proceeding with flushing remote transports.

2、启动Spark的脚本命令：

[hadoop@slaver1 spark-1.5.1-bin-hadoop2.4]$ sbin/start-all.sh

[hadoop@slaver2 ~]$ run-example streaming.NetworkWordCount localhost 9999