新人求教：使用Java接口读取HDFS文件无法成功

[sinat_34977977]

Java代码：

package cn.itcast.hadoop.hdfs;

import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URI;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;

public class HDFSDemo {

	public static void main(String[] args) throws Exception{
		FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), new Configuration());
		InputStream in = fs.open(new Path("/jdk1.7"));
		OutputStream out = new FileOutputStream("d://jdk1.7");
		IOUtils.copyBytes(in, out, 4096, true);
	}

}

异常情况：

log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main" java.net.ConnectException: Call From USER-20160404FC/192.168.8.100 to hadoop01:9000 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:783)
	at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:730)
	at org.apache.hadoop.ipc.Client.call(Client.java:1351)
	at org.apache.hadoop.ipc.Client.call(Client.java:1300)
	at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:206)
	at com.sun.proxy.$Proxy7.getBlockLocations(Unknown Source)
	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:186)
	at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
	at com.sun.proxy.$Proxy7.getBlockLocations(Unknown Source)
	at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getBlockLocations(ClientNamenodeProtocolTranslatorPB.java:188)
	at org.apache.hadoop.hdfs.DFSClient.callGetBlockLocations(DFSClient.java:1064)
	at org.apache.hadoop.hdfs.DFSClient.getLocatedBlocks(DFSClient.java:1054)
	at org.apache.hadoop.hdfs.DFSClient.getLocatedBlocks(DFSClient.java:1044)
	at org.apache.hadoop.hdfs.DFSInputStream.fetchLocatedBlocksAndGetLastBlockLength(DFSInputStream.java:235)
	at org.apache.hadoop.hdfs.DFSInputStream.openInfo(DFSInputStream.java:202)
	at org.apache.hadoop.hdfs.DFSInputStream.<init>(DFSInputStream.java:195)
	at org.apache.hadoop.hdfs.DFSClient.open(DFSClient.java:1212)
	at org.apache.hadoop.hdfs.DistributedFileSystem$3.doCall(DistributedFileSystem.java:290)
	at org.apache.hadoop.hdfs.DistributedFileSystem$3.doCall(DistributedFileSystem.java:286)
	at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
	at org.apache.hadoop.hdfs.DistributedFileSystem.open(DistributedFileSystem.java:286)
	at org.apache.hadoop.fs.FileSystem.open(FileSystem.java:763)
	at cn.itcast.hadoop.hdfs.HDFSDemo.main(HDFSDemo.java:17)
Caused by: java.net.ConnectException: Connection refused: no further information
	at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
	at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
	at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
	at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:529)
	at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:493)
	at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:547)
	at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:642)
	at org.apache.hadoop.ipc.Client$Connection.access$2600(Client.java:314)
	at org.apache.hadoop.ipc.Client.getConnection(Client.java:1399)
	at org.apache.hadoop.ipc.Client.call(Client.java:1318)
	... 24 more

使用web端和Linux可以正常访问：

[张某码]

"hdfs://hadoop01:9000") 你直接用主机名，通过主机名能找到这台主机吗