I'm trying to run a hadoop single unit program for wordcount, I'm doing this on windows 10 64 bit and on Cygwin, this is the program I'm using:
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
public class WordCount {
public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable>
{
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, Text value, Context context) throws IOException, InterruptedException
{
StringTokenizer itr = new StringTokenizer(value.toString());
while (itr.hasMoreTokens())
{
word.set(itr.nextToken());
context.write(word, one);
}
}
}
public static class IntSumReducer extends Reducer<Text,IntWritable,Text,IntWritable>
{
private IntWritable result = new IntWritable();
public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException
{
int sum = 0;
for (IntWritable val : values)
{
sum += val.get();
}
result.set(sum);
context.write(key, result);
}
}
public static void main(String[] args) throws Exception
{
Configuration conf = new Configuration();
Job job = Job.getInstance(conf, "word count");
job.setJarByClass(WordCount.class);
job.setMapperClass(TokenizerMapper.class);
job.setCombinerClass(IntSumReducer.class);
job.setReducerClass(IntSumReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
My classpath is as follows:
~/hadoop-1.2.1/bin/hadoop jar WordCount.jar hadoop.ProcessUnits input_dir output_dir
and I get the following error messages when I try to compile the program:
Exception in thread "main" java.lang.ClassNotFoundException: hadoop.ProcessUnits
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.apache.hadoop.util.RunJar.main(RunJar.java:153)
The problem is that hadoop.ProcessUnits should point to the mainClass you want to run. Your class is called WordCount, so it should look something like:
$ hadoop jar WordCount.jar <PACKAGE>.WordCount input_dir output_dir
Your code doesn't include the package name so I've substituted <PACKAGE>
Related
I want to run the code described in this tutorial in order to customize the output format in Hadoop. More precisely, the tutorial shows two java files:
WordCount: is the word count java application (similar to the WordCount v1.0 of the MapReduce Tutorial in this link)
XMLOutputFormat: java class that extends FileOutputFormat and implements the method to customize the output.
Well, what I did was to take the WordCount v1.0 of the MapReduce Tutorial (instead of using the WordCount showed in the tutorial) and add in the driver job.setOutputFormatClass(XMLOutputFormat.class); and execute the hadoop app in this way:
/usr/local/hadoop/bin/hadoop com.sun.tools.javac.Main WordCount.java && jar cf wc.jar WordCount*.class && /usr/local/hadoop/bin/hadoop jar wc.jar WordCount /home/luis/Desktop/mytest/input/ ./output_folder
note: /home/luis/Desktop/mytest/input/ and ./output_folder are the input and output folders, respectively.
Unfortunately, the terminal shows me the following error:
WordCount.java:57: error: cannot find symbol
job.setOutputFormatClass(XMLOutputFormat.class);
^
symbol: class XMLOutputFormat
location: class WordCount
1 error
Why? WordCount.java and XMLOutputFormat.java are stored in the same folder.
The following is my code.
WordCount code:
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
public class WordCount {
public static class TokenizerMapper
extends Mapper<Object, Text, Text, IntWritable>{
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, Text value, Context context
) throws IOException, InterruptedException {
StringTokenizer itr = new StringTokenizer(value.toString());
while (itr.hasMoreTokens()) {
word.set(itr.nextToken());
context.write(word, one);
}
}
}
public static class IntSumReducer
extends Reducer<Text,IntWritable,Text,IntWritable> {
private IntWritable result = new IntWritable();
public void reduce(Text key, Iterable<IntWritable> values,
Context context
) throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
sum += val.get();
}
result.set(sum);
context.write(key, result);
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
Job job = Job.getInstance(conf, "word count");
job.setJarByClass(WordCount.class);
job.setMapperClass(TokenizerMapper.class);
job.setCombinerClass(IntSumReducer.class);
job.setReducerClass(IntSumReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
job.setOutputFormatClass(XMLOutputFormat.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
XMLOutputFormat code:
import java.io.DataOutputStream;
import java.io.IOException;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
public class XMLOutputFormat extends FileOutputFormat<Text, IntWritable> {
protected static class XMLRecordWriter extends RecordWriter<Text, IntWritable> {
private DataOutputStream out;
public XMLRecordWriter(DataOutputStream out) throws IOException{
this.out = out;
out.writeBytes("<Output>\n");
}
private void writeStyle(String xml_tag,String tag_value) throws IOException {
out.writeBytes("<"+xml_tag+">"+tag_value+"</"+xml_tag+">\n");
}
public synchronized void write(Text key, IntWritable value) throws IOException {
out.writeBytes("<record>\n");
this.writeStyle("key", key.toString());
this.writeStyle("value", value.toString());
out.writeBytes("</record>\n");
}
public synchronized void close(TaskAttemptContext job) throws IOException {
try {
out.writeBytes("</Output>\n");
} finally {
out.close();
}
}
}
public RecordWriter<Text, IntWritable> getRecordWriter(TaskAttemptContext job) throws IOException {
String file_extension = ".xml";
Path file = getDefaultWorkFile(job, file_extension);
FileSystem fs = file.getFileSystem(job.getConfiguration());
FSDataOutputStream fileOut = fs.create(file, false);
return new XMLRecordWriter(fileOut);
}
}
You need to either add package testpackage; at the beginning of your WordCount class
or
import testpackage.XMLOutputFormat; in your WordCount class.
Because they are in the same directory, it doesn't imply they are in the same package.
We will need to add the XMLOutputFormat.jar file to the HADOOP_CLASSPATH first for the driver code to find it. And pass it in -libjars option to be added to classpath of the map and reduce jvms.
export HADOOP_CLASSPATH=$HADOOP_CLASSPATH:/abc/xyz/XMLOutputFormat.jar
yarn jar wordcount.jar com.sample.test.Wordcount
-libjars /path/to/XMLOutputFormat.jar
/lab/mr/input /lab/output/output
I am new to Hadoop, and trying the example of WordCount V1.0 here:
https://www.cloudera.com/documentation/other/tutorial/CDH5/topics/ht_usage.html
However, when I compile the WordCount.java using this line:
javac -cp /usr/lib/hadoop/*:/usr/lib/hadoop-mapreduce/* WordCount.java -d build -Xlint
It seems like the code uses the old version of .jar files, and gives me the following warnings (as shown in the picture). However, when I check inside the classpath I declared, there are some .jar files which seems to be newer versions of those being required .jar files.
So my question is that how can I make my WordCount.java use the newer file instead? I tried looking inside the WordCount.java code to see which rows use those required .jar files but could not see them.
Thanks in advance for any help.
The code of the WordCount.java
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
public class WordCount {
public static class TokenizerMapper
extends Mapper<Object, Text, Text, IntWritable>{
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, Text value, Context context
) throws IOException, InterruptedException {
StringTokenizer itr = new StringTokenizer(value.toString());
while (itr.hasMoreTokens()) {
word.set(itr.nextToken());
context.write(word, one);
}
}
}
public static class IntSumReducer
extends Reducer<Text,IntWritable,Text,IntWritable> {
private IntWritable result = new IntWritable();
public void reduce(Text key, Iterable<IntWritable> values,
Context context
) throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
sum += val.get();
}
result.set(sum);
context.write(key, result);
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
Job job = Job.getInstance(conf, "word count");
job.setJarByClass(WordCount.class);
job.setMapperClass(TokenizerMapper.class);
job.setCombinerClass(IntSumReducer.class);
job.setReducerClass(IntSumReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
I have set up Hadoop 2.6.0 on 2 Vm's each running CentOS 6.5(64 bit) ,Yarn as well as Hadoop is running fine. My host m/c is Windows 8.1 (64 bit) I am trying to run Word Count map reduce problem from Eclipse on my host machine while the cluster is running on VMN's but getting exception
package com.mapr.example;
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
public class WordCount {
public static class TokenizerMapper
extends Mapper<Object, Text, Text, IntWritable>{
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, Text value, Context context
) throws IOException, InterruptedException {
StringTokenizer itr = new StringTokenizer(value.toString());
while (itr.hasMoreTokens()) {
word.set(itr.nextToken());
context.write(word, one);
}
}
}
public static class IntSumReducer
extends Reducer<Text,IntWritable,Text,IntWritable> {
private IntWritable result = new IntWritable();
public void reduce(Text key, Iterable<IntWritable> values,
Context context
) throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
sum += val.get();
}
result.set(sum);
context.write(key, result);
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
Job job = Job.getInstance(conf, "word count");
job.setJarByClass(WordCount.class);
job.setMapperClass(TokenizerMapper.class);
job.setCombinerClass(IntSumReducer.class);
job.setReducerClass(IntSumReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path("D:\\MyworkSpace\\MapReducePractice\\resource\\Input.txt"));
FileOutputFormat.setOutputPath(job, new Path("D:\\MyworkSpace\\MapReducePractice\\resource\\Output"));
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
Exception that i am getting
Exception in thread "main" java.lang.NullPointerException
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1011)
at org.apache.hadoop.util.Shell.runCommand(Shell.java:482)
at org.apache.hadoop.util.Shell.run(Shell.java:455)
at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:715)
at org.apache.hadoop.util.Shell.execCommand(Shell.java:808)
at org.apache.hadoop.util.Shell.execCommand(Shell.java:791)
at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:656)
at org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:444)
at org.apache.hadoop.fs.FilterFileSystem.mkdirs(FilterFileSystem.java:293)
at org.apache.hadoop.mapreduce.JobSubmissionFiles.getStagingDir(JobSubmissionFiles.java:133)
at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:437)
at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1296)
at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1293)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1628)
at org.apache.hadoop.mapreduce.Job.submit(Job.java:1293)
at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1314)
at com.mapr.example.WordCount.main(WordCount.java:72)
Any pointers will be of a great help.
I have installed Hadoop version 2.2.0 on Ubuntu. When I run:
yarn jar
hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.2.0.jar
wordcount /user/ubuntu/wordcount/input/file01.txt /output
It runs fine.
When I run a sample program, make the JAR using Eclipse export utility, and run using:
yarn jar /user/ubuntu/WordCountNew.jar com.sample.WordCountNew
/user/ubuntu/wordcount/input/file01.txt /output9
It shows: Not a valid JAR: /user/ubuntu/WordCountNew.jar
When I compile the code in Eclipse, it also shows this error:
2015-02-02 16:08:53,077 WARN [main] util.NativeCodeLoader (NativeCodeLoader.java:<clinit>(62)) - Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at com.kumar.WordCountNew.main(WordCountNew.java:62)
Code:
package com.sample;
import java.io.IOException;
import java.util.*;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapreduce.*;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
public class WordCountNew {
public static class Map extends Mapper<LongWritable, Text, Text, IntWritable> {
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
String line = value.toString();
StringTokenizer tokenizer = new StringTokenizer(line);
while (tokenizer.hasMoreTokens()) {
word.set(tokenizer.nextToken());
context.write(word, one);
}
}
}
public static class Reduce extends Reducer<Text, IntWritable, Text, IntWritable> {
public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
sum = sum + val.get();
context.write(key, new IntWritable(sum));
}
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
Job job = new Job(conf, "wordcount");
job.setJarByClass(WordCountNew.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
job.setMapperClass(Map.class);
job.setReducerClass(Reduce.class);
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job,new Path(args[1]));
job.waitForCompletion(true);
}
}
I am currently wanting to create a single instance node of Hadoop. So I am following this tutorial. I ran the following command in terminal:
hduser#ubuntu:/usr/local/hadoop$ bin/hadoop jar WordCount.jar geekyomega.WordCount /user/hduser/gutenberg /user/hduser/gutenberg-output
Things were going great until I ran into this error:
Exception in thread "main" java.lang.ClassNotFoundException: WordCount
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:270)
at org.apache.hadoop.util.RunJar.main(RunJar.java:153)
I am attempting to run this example using the following code, where I got from here. Here is my version of the code:
package geekyomega;
import java.io.IOException;
import java.util.*;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapreduce.*;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
public class WordCount {
public static class Map extends Mapper<LongWritable, Text, Text, IntWritable> {
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
String line = value.toString();
StringTokenizer tokenizer = new StringTokenizer(line);
while (tokenizer.hasMoreTokens()) {
word.set(tokenizer.nextToken());
context.write(word, one);
}
}
}
public static class Reduce extends Reducer<Text, IntWritable, Text, IntWritable> {
public void reduce(Text key, Iterable<IntWritable> values, Context context)
throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
sum += val.get();
}
context.write(key, new IntWritable(sum));
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
Job job = new Job(conf, "WordCount");
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
job.setMapperClass(Map.class);
job.setReducerClass(Reduce.class);
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
job.waitForCompletion(true);
}
}
I thought my issue was job instantiation. So I did as follows, I changed:
Job job = new Job(conf, "wordcount");
To the following, capitalized version:
Job job = new Job(conf, "WordCount");
But that hasn't helped. Anyone know what could help me here?
Thanks,
Geeky
PS - I don't want to run the tutorial version of wordcount. What I did was created the project in eclipse, added the hadoop jar to it, and exported it as a jar file.
your classname is geekyomega.WordCount
you are not appending the package name . in the command line , just after jar file name, give the fully qualified name of your job class.
Along with adding the package add the following line as well in the job config part of your program :
job.setJarByClass(WordCount.class);