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POError in reading a txt file on HDFS and copying/writing the content of it into a newly created file on LOCAL filesystem
 

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  1. POError in reading a txt file on HDFS and copying/writing the content of it into a newly created file on LOCAL filesystem
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    <p>I am trying to read a file on HDFS and copy the content of the file into a newly created local file using the following java program. FYI, I have installed hadoop single node cluster on my machine.</p> <p>HdfsCli.java</p> <pre><code>package com; import java.io.BufferedOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FSDataInputStream; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; public class HdfsCli { public void readFile(String file) throws IOException { Configuration conf = new Configuration(); String hadoopConfPath = "\\opt\\hadoop\\etc\\hadoop\\"; conf.addResource(new Path(hadoopConfPath + "core-site.xml")); conf.addResource(new Path(hadoopConfPath + "hdfs-site.xml")); conf.addResource(new Path(hadoopConfPath + "mapred-site.xml")); FileSystem fileSystem = FileSystem.get(conf); // For the join type of queries, output file in the HDFS has 'r' in it. // String type="r"; Path path = new Path(file); if (!fileSystem.exists(path)) { System.out.println("File " + file + " does not exists"); return; } FSDataInputStream in = fileSystem.open(path); String filename = file.substring(file.lastIndexOf('/') + 1, file.length()); OutputStream out = new BufferedOutputStream(new FileOutputStream( new File("/home/DAS_Pig/" + filename))); byte[] b = new byte[1024]; int numBytes = 0; while ((numBytes = in.read(b)) &gt; 0) { out.write(b, 0, numBytes); } conf.clear(); in.close(); out.close(); fileSystem.close(); } public static void main(String[] args) throws IOException { // TODO Auto-generated method stub HDFSClient hc = new HDFSClient(); hc.readFile("hdfs://localhost:9000//DasData//salaries.txt"); System.out.println("Successfully Done!"); } } </code></pre> <p>However, when I am running this code, the following error is coming:</p> <pre><code>Exception in thread "main" org.apache.hadoop.ipc.RemoteException: Server IPC version 9 cannot communicate with client version 4 at org.apache.hadoop.ipc.Client.call(Client.java:1066) at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:225) at com.sun.proxy.$Proxy1.getProtocolVersion(Unknown Source) at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:396) at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:379) at org.apache.hadoop.hdfs.DFSClient.createRPCNamenode(DFSClient.java:119) at org.apache.hadoop.hdfs.DFSClient.&lt;init&gt;(DFSClient.java:238) at org.apache.hadoop.hdfs.DFSClient.&lt;init&gt;(DFSClient.java:203) at org.apache.hadoop.hdfs.DistributedFileSystem.initialize(DistributedFileSystem.java:89) at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:1386) at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:66) at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:1404) at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:254) at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:123) at com.HDFSClient.readFile(HDFSClient.java:22) at com.HdfsCli.main(HdfsCli.java:57) </code></pre> <p>I am newb in hadoop development. Can anyone guide me in resolving this? Thank you!</p>
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