hadoop helloworld on Mac OS

hadoop helloworld on Mac OS

install maven

  • brew install maven

create a java project

  • mvn archetype:generate
    Choose a number or apply filter (format: [groupId:]artifactId, case sensitive contains): 436:
    Choose org.apache.maven.archetypes:maven-archetype-quickstart version:
    1: 1.0-alpha-1
    2: 1.0-alpha-2
    3: 1.0-alpha-3
    4: 1.0-alpha-4
    5: 1.0
    6: 1.1
    Choose a number: 6:
    Define value for property 'groupId': : helloworld
    Define value for property 'artifactId': : hadoop
    Define value for property 'version':  1.0-SNAPSHOT: :
    Define value for property 'package':  helloworld: :
    Confirm properties configuration:
    groupId: helloworld
    artifactId: hadoop
    version: 1.0-SNAPSHOT
    package: helloworld
     Y: :
     [INFO] ----------------------------------------------------------------------------
    [INFO] Using following parameters for creating project from Old (1.x) Archetype: maven-archetype-quickstart:1.1
    [INFO] ----------------------------------------------------------------------------
    [INFO] Parameter: groupId, Value: helloworld
    [INFO] Parameter: packageName, Value: helloworld
    [INFO] Parameter: package, Value: helloworld
    [INFO] Parameter: artifactId, Value: hadoop
    [INFO] Parameter: basedir, Value: /Users/username/Documents/src
    [INFO] Parameter: version, Value: 1.0-SNAPSHOT
    [INFO] project created from Old (1.x) Archetype in dir: /Users/username/Documents/src/hadoop
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESS
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time: 01:26 min
    [INFO] Finished at: 2014-07-01T19:55:19+09:00
    [INFO] Final Memory: 10M/81M
    [INFO] ------------------------------------------------------------------------</li>
    

write map reduce source

  • src/main/java/helloworld/Map.java (Mapper Implementation)

    package helloworld;
    import java.io.IOException;
    import java.util.StringTokenizer;
    import org.apache.hadoop.io.IntWritable;
    import org.apache.hadoop.io.LongWritable;
    import org.apache.hadoop.io.Text;
    import org.apache.hadoop.mapred.MapReduceBase;
    import org.apache.hadoop.mapred.Mapper;
    import org.apache.hadoop.mapred.OutputCollector;
    import org.apache.hadoop.mapred.Reporter;
    public class Map extends MapReduceBase implements 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, OutputCollector<Text, IntWritable> output, Reporter reporter)
     throws IOException
     {
     String line = value.toString();
     StringTokenizer tokenizer = new StringTokenizer(line);
     while (tokenizer.hasMoreTokens())
     {
     word.set(tokenizer.nextToken());
     output.collect(word, one);
     }
     }
    }
    
  • src/main/java/helloworld/Reduce.java (Reducer Implementation)

    package helloworld;
    import java.io.IOException;
    import java.util.Iterator;
    import org.apache.hadoop.io.IntWritable;
    import org.apache.hadoop.io.Text;
    import org.apache.hadoop.mapred.MapReduceBase;
    import org.apache.hadoop.mapred.OutputCollector;
    import org.apache.hadoop.mapred.Reducer;
    import org.apache.hadoop.mapred.Reporter;
    public class Reduce extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable>
    {
     public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output,
     Reporter reporter) throws IOException
     {
     int sum = 0;
     while (values.hasNext())
     {
     sum += values.next().get();
     }
     output.collect(key, new IntWritable(sum));
     }
    }
    
  • src/main/java/helloworld/App.java (Job)

    package helloworld;
    import org.apache.hadoop.fs.Path;
    import org.apache.hadoop.io.IntWritable;
    import org.apache.hadoop.io.Text;
    import org.apache.hadoop.mapred.FileInputFormat;
    import org.apache.hadoop.mapred.FileOutputFormat;
    import org.apache.hadoop.mapred.JobClient;
    import org.apache.hadoop.mapred.JobConf;
    import org.apache.hadoop.mapred.TextInputFormat;
    import org.apache.hadoop.mapred.TextOutputFormat;
    /**
     * Hello world!
     *
     */
    public class App
    {
      public static void main( String[] args ) throws Exception
      {
          System.out.println( "Hello World!" );
          JobConf conf = new JobConf(App.class);
          conf.setJobName("wordcount");
          conf.setOutputKeyClass(Text.class);
          conf.setOutputValueClass(IntWritable.class);
          conf.setMapperClass(Map.class);
          conf.setCombinerClass(Reduce.class);
          conf.setReducerClass(Reduce.class);
          conf.setInputFormat(TextInputFormat.class);
          conf.setOutputFormat(TextOutputFormat.class);
          FileInputFormat.setInputPaths(conf, new Path(args[0]));
          FileOutputFormat.setOutputPath(conf, new Path(args[1]));
          JobClient.runJob(conf);
      }
    }
    

compile and create Jar file

  • mvn clean install

run MapReduce job

  • /usr/local/Cellar/hadoop/2.4.0/bin/hadoop jar target/hadoop-1.0-SNAPSHOT.jar helloworld.App input/*.xml output3
  • hadoop dfs -ls output3

    Found 2 items
    -rw-r--r--   1 username supergroup          0 2014-07-01 22:23 output3/_SUCCESS
    -rw-r--r--   1 username supergroup       5938 2014-07-01 22:23 output3/part-00000</li>
    

first hadoop
maven create project



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