java.net.ConnectException: Connection refused: no further information【已解决】

 报错如下：

java.net.ConnectException: Call From V_LZ/192.168.53.1 to hadoop2:8020 failed on connection exception: java.net.ConnectException: Connection refused: no further information; 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:791)
	at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:731)
	at org.apache.hadoop.ipc.Client.call(Client.java:1472)
	at org.apache.hadoop.ipc.Client.call(Client.java:1399)
	at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:232)
	at com.sun.proxy.$Proxy9.getFileInfo(Unknown Source)
	at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getFileInfo(ClientNamenodeProtocolTranslatorPB.java:752)
	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:187)
	at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
	at com.sun.proxy.$Proxy10.getFileInfo(Unknown Source)
	at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:1988)
	at org.apache.hadoop.hdfs.DistributedFileSystem$18.doCall(DistributedFileSystem.java:1118)
	at org.apache.hadoop.hdfs.DistributedFileSystem$18.doCall(DistributedFileSystem.java:1114)
	at org.apache.hadoop.fs.FileSystemlinkResolver.resolve(FileSystemlinkResolver.java:81)
	at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1114)
	at org.apache.hadoop.fs.FileSystem.exists(FileSystem.java:1400)
	at com.lens.task.HdfsOperate.main(HdfsOperate.java:22)
Caused by: java.net.ConnectException: Connection refused: no further information
	at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
	at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
	at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
	at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:530)
	at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:494)
	at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:607)
	at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:705)
	at org.apache.hadoop.ipc.Client$Connection.access$2800(Client.java:368)
	at org.apache.hadoop.ipc.Client.getConnection(Client.java:1521)
	at org.apache.hadoop.ipc.Client.call(Client.java:1438)
	... 18 more

Process finished with exit code 0

原因：端口不一致，客户端无法访问服务端

解决方法：把客户端的端口改成服务端一致的端口

ok,大功告成 。

8020端口：

8020端口在Hadoop1.x中默认承担着Namenode 和 Datanode之间的心跳通信，也兼顾FileSystem默认的端口号(Hdfs客户端访问Hdfs集群的RPC通信端口)，
但是在Hadoop2.x中，8020只承担了namenode 和 datanode之间的心跳通信，当然这些端口的设置是指的默认设置。

	fs.defaultFS
	hdfs://hadoop01:8020

9000端口：

9000端口是在Hadoop2.x中将FileSystem通讯端口拆分出来了，默认为9000，在Hadoop2.x中我们可以在hdfs-size.xml中进行配置。

50070端口是httpService访问端口，供于浏览器进行访问Namenode节点，监控其各个Datanode的服务端口，同样在Hadoop2.x中我们可以在hdfs-size.xml中进行配置。