【hadoop】 3002-mapreduce程序统计单词个数示例

[hadoop@cloud01 HDFSdemo]$ hadoop fs -cat /wc/wordcount.txt
hello world
hello China
hello wenjie
hello USA
hello China
hello China
hello Japan

[hadoop@cloud01 HDFSdemo]$ hadoop fs -cat /wc/wordcount1.txt
hello USA

期望结果：

<hello,8>,<world,1><China,3><wenjie,1>,<USA，2>,<Japan,1>

package mapreduce;

import java.io.IOException;

import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;

/**
* Mapper
*
* @author shenfl
*
*/
public class WCMapper extends Mapper<LongWritable, Text, Text, LongWritable> {

     /**
     *  @param key : text offset
     *  @param value: each line text
     *  @context : hadoop context
     */
     protected void map(LongWritable key, Text value, Context context) throws IOException,
          InterruptedException {

          String[] values = StringUtils.split(value.toString(), " ");
         
          for(String v:values){
               context.write(new Text(v),new LongWritable(1));
          }
     }
}

package mapreduce;

import java.io.IOException;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

public class WCReducer extends Reducer<Text, LongWritable, Text, LongWritable> {

     @Override
     protected void reduce(Text key, Iterable<LongWritable> values, Context context) throws IOException,
               InterruptedException {

          long count = 0;
          for(LongWritable v:values){
               count += v.get();
          }
          context.write(key, new  LongWritable(count));
     }
}

package mapreduce;

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.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
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;

/**
* <p>
* Test hadoop 2.4.1 version program
* </p>
*
* @author shenfl
*
*/
public class WordCount {

     private static final String HDFS_PATH = "hdfs://cloud01:9000";

     public static void main(String[] args) {

          Configuration conf = new Configuration();
          try {
               // conf.set("", "");
               Job job = Job.getInstance(conf);

               /**
               * Set the job‘s jar file by finding an example class location.
               *
               * @param cls
               *            the example class.
               */
               job.setJarByClass(WordCount.class);
               job.setJar("wc.jar");
              
               job.setInputFormatClass(TextInputFormat.class);
               job.setOutputFormatClass(TextOutputFormat.class);

               job.setMapperClass(WCMapper.class);
               job.setReducerClass(WCReducer.class);

               job.setMapOutputKeyClass(Text.class);
               job.setMapOutputValueClass(LongWritable.class);

               job.setOutputKeyClass(Text.class);
               job.setOutputKeyClass(LongWritable.class);

               Path inputPath = new Path(HDFS_PATH + "/wc");
               Path outputDir = new Path(HDFS_PATH + "/tmp");
               /**
               * Set the array of as the list of inputs for the
               * map-reduce job.
               * @param job The job to modify
               * @param inputPaths
               *            the of the input directories/files for
               *            the map-reduce job.
               */
               FileInputFormat.setInputPaths(job, inputPath);
               /**
               * Set the of the output directory for the map-reduce
               * job.
               * @param job The job to modify
               * @param outputDir
               *            the of the output directory for the
               *            map-reduce job.
               */
               FileOutputFormat.setOutputPath(job, outputDir);

               FileSystem fs = FileSystem.get(new URI(HDFS_PATH), conf);
               if (fs.exists(outputDir)) {
                    fs.delete(outputDir, true);
               }
               System.exit(job.waitForCompletion(true) ? 0 : 1);
          } catch (Exception e) {
               e.printStackTrace();
          }
     }

}

[hadoop@cloud01 HDFSdemo]$ hadoop fs -cat /tmp/part-r-00000
China     3
Japan     1
USA     2
hello     8
wenjie     1
world     1

2015-02-24 22:37:09,812 WARN  [main] util.NativeCodeLoader ( NativeCodeLoader.java:<clinit>(62) ) - Unable to load native-hadoop library for your platform... using builtin-java classes where applicable

2015-02-24 22:37:10,673 INFO  [main] Configuration.deprecation (Configuration.java:warnOnceIfDeprecated(1009) ) - session.id is deprecated. Instead, use dfs.metrics.session-id

2015-02-24 22:37:10,674 INFO  [main] jvm.JvmMetrics ( JvmMetrics.java:init(76)) - Initializing JVM Metrics with processName=JobTracker, sessionId=

2015-02-24 22:37:10,958 WARN  [main] mapreduce.JobSubmitter (JobSubmitter.java:copyAndConfigureFiles(150) ) - Hadoop command-line option parsing not performed. Implement the Tool interface and execute your application with ToolRunner to remedy this.

2015-02-24 22:37:14,867 INFO  [main] input.FileInputFormat ( FileInputFormat.java:listStatus(280) ) - Total input paths to process : 2

2015-02-24 22:37:14,987 INFO  [main] mapreduce.JobSubmitter ( JobSubmitter.java:submitJobInternal(396) ) - number of splits:2

2015-02-24 22:37:15,165 INFO  [main] mapreduce.JobSubmitter ( JobSubmitter.java:printTokens(479) ) - Submitting tokens for job: job_local1376201216_0001

2015-02-24 22:37:15,193 WARN  [main] conf.Configuration ( Configuration.java:loadProperty(2358) ) - file:/tmp/hadoop-hadoop/mapred/staging/hadoop1376201216/.staging/job_local1376201216_0001/job.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.retry.interval;  Ignoring.

2015-02-24 22:37:15,194 WARN  [main] conf.Configuration ( Configuration.java:loadProperty(2358) ) - file:/tmp/hadoop-hadoop/mapred/staging/hadoop1376201216/.staging/job_local1376201216_0001/job.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.attempts;  Ignoring.

2015-02-24 22:37:15,386 WARN  [main] conf.Configuration ( Configuration.java:loadProperty(2358) ) - file:/tmp/hadoop-hadoop/mapred/local/localRunner/hadoop/job_local1376201216_0001/job_local1376201216_0001.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.retry.interval;  Ignoring.

2015-02-24 22:37:15,387 WARN  [main] conf.Configuration ( Configuration.java:loadProperty(2358) ) - file:/tmp/hadoop-hadoop/mapred/local/localRunner/hadoop/job_local1376201216_0001/job_local1376201216_0001.xml:an attempt to override final parameter: mapreduce.job.end-notification.max.attempts;  Ignoring.

2015-02-24 22:37:15,401 INFO  [main] mapreduce.Job ( Job.java:submit(1289)) - The url to track the job: http://localhost:8080/

2015-02-24 22:37:15,401 INFO  [main] mapreduce.Job ( Job.java:monitorAndPrintJob(1334) ) - Running job: job_local1376201216_0001

2015-02-24 22:37:15,431 INFO  [Thread-14] mapred.LocalJobRunner (LocalJobRunner.java:createOutputCommitter(471) ) - OutputCommitter set in config null

2015-02-24 22:37:15,453 INFO  [Thread-14] mapred.LocalJobRunner (LocalJobRunner.java:createOutputCommitter(489) ) - OutputCommitter is org.apache.hadoop.mapreduce.lib.output.FileOutputCommitter

2015-02-24 22:37:15,583 INFO  [Thread-14] mapred.LocalJobRunner ( LocalJobRunner.java:runTasks(448) ) - Waiting for map tasks

2015-02-24 22:37:15,588 INFO  [LocalJobRunner Map Task Executor #0] mapred.LocalJobRunner (LocalJobRunner.java:run(224) ) - Starting task: attempt_local1376201216_0001_m_000000_0

2015-02-24 22:37:15,723 INFO  [LocalJobRunner Map Task Executor #0] mapred.Task (Task.java:initialize(581) ) -  Using ResourceCalculatorProcessTree : [ ]

2015-02-24 22:37:15,726 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:runNewMapper(733) ) - Processing split: hdfs://cloud01:9000/wc/wordcount.txt:0+84

2015-02-24 22:37:15,754 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:createSortingCollector(388) ) - Map output collector class = org.apache.hadoop.mapred.MapTask$MapOutputBuffer

2015-02-24 22:37:15,876 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:setEquator(1182) ) - (EQUATOR) 0 kvi 26214396(104857584)

2015-02-24 22:37:15,877 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:init(975) ) - mapreduce.task.io.sort.mb: 100

2015-02-24 22:37:15,877 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:init(976) ) - soft limit at 83886080

2015-02-24 22:37:15,877 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:init(977) ) - bufstart = 0; bufvoid = 104857600

2015-02-24 22:37:15,877 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:init(978) ) - kvstart = 26214396; length = 6553600

2015-02-24 22:37:16,435 INFO  [main] mapreduce.Job ( Job.java:monitorAndPrintJob(1355) ) - Job job_local1376201216_0001 running in uber mode : false

2015-02-24 22:37:16,552 INFO  [main] mapreduce.Job ( Job.java:monitorAndPrintJob(1362) ) -  map 0% reduce 0%

2015-02-24 22:37:17,104 INFO  [LocalJobRunner Map Task Executor #0] mapred.LocalJobRunner (LocalJobRunner.java:statusUpdate(591) ) -

2015-02-24 22:37:17,106 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:flush(1437) ) - Starting flush of map output

2015-02-24 22:37:17,106 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:flush(1455) ) - Spilling map output

2015-02-24 22:37:17,106 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:flush(1456) ) - bufstart = 0; bufend = 195; bufvoid = 104857600

2015-02-24 22:37:17,106 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:flush(1458) ) - kvstart = 26214396(104857584); kvend = 26214344(104857376); length = 53/6553600

2015-02-24 22:37:17,113 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:sortAndSpill(1641) ) - Finished spill 0

2015-02-24 22:37:17,116 INFO  [LocalJobRunner Map Task Executor #0] mapred.Task ( Task.java:done(995)) - Task:attempt_local1376201216_0001_m_000000_0 is done. And is in the process of committing

2015-02-24 22:37:17,123 INFO  [LocalJobRunner Map Task Executor #0] mapred.LocalJobRunner (LocalJobRunner.java:statusUpdate(591) ) - map

2015-02-24 22:37:17,123 INFO  [LocalJobRunner Map Task Executor #0] mapred.Task (Task.java:sendDone(1115) ) - Task ‘attempt_local1376201216_0001_m_000000_0‘ done.

2015-02-24 22:37:17,123 INFO  [LocalJobRunner Map Task Executor #0] mapred.LocalJobRunner (LocalJobRunner.java:run(249) ) - Finishing task: attempt_local1376201216_0001_m_000000_0

2015-02-24 22:37:17,123 INFO  [LocalJobRunner Map Task Executor #0] mapred.LocalJobRunner (LocalJobRunner.java:run(224) ) - Starting task: attempt_local1376201216_0001_m_000001_0

2015-02-24 22:37:17,124 INFO  [LocalJobRunner Map Task Executor #0] mapred.Task (Task.java:initialize(581) ) -  Using ResourceCalculatorProcessTree : [ ]

2015-02-24 22:37:17,125 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:runNewMapper(733) ) - Processing split: hdfs://cloud01:9000/wc/wordcount1.txt:0+11

2015-02-24 22:37:17,125 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:createSortingCollector(388) ) - Map output collector class = org.apache.hadoop.mapred.MapTask$MapOutputBuffer

2015-02-24 22:37:17,172 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:setEquator(1182) ) - (EQUATOR) 0 kvi 26214396(104857584)

2015-02-24 22:37:17,172 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:init(975) ) - mapreduce.task.io.sort.mb: 100

2015-02-24 22:37:17,172 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:init(976) ) - soft limit at 83886080

2015-02-24 22:37:17,173 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:init(977) ) - bufstart = 0; bufvoid = 104857600

2015-02-24 22:37:17,173 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:init(978) ) - kvstart = 26214396; length = 6553600

2015-02-24 22:37:17,180 INFO  [LocalJobRunner Map Task Executor #0] mapred.LocalJobRunner (LocalJobRunner.java:statusUpdate(591) ) -

2015-02-24 22:37:17,180 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:flush(1437) ) - Starting flush of map output

2015-02-24 22:37:17,180 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:flush(1455) ) - Spilling map output

2015-02-24 22:37:17,180 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:flush(1456) ) - bufstart = 0; bufend = 26; bufvoid = 104857600

2015-02-24 22:37:17,180 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:flush(1458) ) - kvstart = 26214396(104857584); kvend = 26214392(104857568); length = 5/6553600

2015-02-24 22:37:17,182 INFO  [LocalJobRunner Map Task Executor #0] mapred.MapTask (MapTask.java:sortAndSpill(1641) ) - Finished spill 0

2015-02-24 22:37:17,183 INFO  [LocalJobRunner Map Task Executor #0] mapred.Task ( Task.java:done(995)) - Task:attempt_local1376201216_0001_m_000001_0 is done. And is in the process of committing

2015-02-24 22:37:17,187 INFO  [LocalJobRunner Map Task Executor #0] mapred.LocalJobRunner (LocalJobRunner.java:statusUpdate(591) ) - map

2015-02-24 22:37:17,188 INFO  [LocalJobRunner Map Task Executor #0] mapred.Task (Task.java:sendDone(1115) ) - Task ‘attempt_local1376201216_0001_m_000001_0‘ done.

2015-02-24 22:37:17,188 INFO  [LocalJobRunner Map Task Executor #0] mapred.LocalJobRunner (LocalJobRunner.java:run(249) ) - Finishing task: attempt_local1376201216_0001_m_000001_0

2015-02-24 22:37:17,188 INFO  [Thread-14] mapred.LocalJobRunner ( LocalJobRunner.java:runTasks(456) ) - map task executor complete.

2015-02-24 22:37:17,201 INFO  [Thread-14] mapred.LocalJobRunner ( LocalJobRunner.java:runTasks(448) ) - Waiting for reduce tasks

2015-02-24 22:37:17,201 INFO  [pool-6-thread-1] mapred.LocalJobRunner ( LocalJobRunner.java:run(302) ) - Starting task: attempt_local1376201216_0001_r_000000_0

2015-02-24 22:37:17,212 INFO  [pool-6-thread-1] mapred.Task ( Task.java:initialize(581)) -  Using ResourceCalculatorProcessTree : [ ]

2015-02-24 22:37:17,215 INFO  [pool-6-thread-1] mapred.ReduceTask ( ReduceTask.java:run(362)) - Using ShuffleConsumerPlugin: org.apache.hadoop.mapreduce.task.reduce.Shuffle@b76539

2015-02-24 22:37:17,248 INFO  [pool-6-thread-1] reduce.MergeManagerImpl (MergeManagerImpl.java:<init>(193) ) - MergerManager: memoryLimit=178821520, maxSingleShuffleLimit=44705380, mergeThreshold=118022208, ioSortFactor=10, memToMemMergeOutputsThreshold=10

2015-02-24 22:37:17,256 INFO  [EventFetcher for fetching Map Completion Events] reduce.EventFetcher (EventFetcher.java:run(61) ) - attempt_local1376201216_0001_r_000000_0 Thread started: EventFetcher for fetching Map Completion Events

2015-02-24 22:37:17,374 INFO  [localfetcher#1] reduce.LocalFetcher (LocalFetcher.java:copyMapOutput(140) ) - localfetcher#1 about to shuffle output of map attempt_local1376201216_0001_m_000000_0 decomp: 225 len: 229 to MEMORY

2015-02-24 22:37:17,412 INFO  [localfetcher#1] reduce.InMemoryMapOutput (InMemoryMapOutput.java:shuffle(100) ) - Read 225 bytes from map-output for attempt_local1376201216_0001_m_000000_0

2015-02-24 22:37:17,421 INFO  [localfetcher#1] reduce.MergeManagerImpl (MergeManagerImpl.java:closeInMemoryFile(307) ) - closeInMemoryFile -> map-output of size: 225, inMemoryMapOutputs.size() -> 1, commitMemory -> 0, usedMemory ->225

2015-02-24 22:37:17,462 INFO  [localfetcher#1] reduce.LocalFetcher (LocalFetcher.java:copyMapOutput(140) ) - localfetcher#1 about to shuffle output of map attempt_local1376201216_0001_m_000001_0 decomp: 32 len: 36 to MEMORY

2015-02-24 22:37:17,468 INFO  [localfetcher#1] reduce.InMemoryMapOutput (InMemoryMapOutput.java:shuffle(100) ) - Read 32 bytes from map-output for attempt_local1376201216_0001_m_000001_0

2015-02-24 22:37:17,469 INFO  [localfetcher#1] reduce.MergeManagerImpl (MergeManagerImpl.java:closeInMemoryFile(307) ) - closeInMemoryFile -> map-output of size: 32, inMemoryMapOutputs.size() -> 2, commitMemory -> 225, usedMemory ->257

2015-02-24 22:37:17,477 INFO  [EventFetcher for fetching Map Completion Events] reduce.EventFetcher (EventFetcher.java:run(76) ) - EventFetcher is interrupted.. Returning

2015-02-24 22:37:17,480 INFO  [pool-6-thread-1] mapred.LocalJobRunner (LocalJobRunner.java:statusUpdate(591) ) - 2 / 2 copied.

2015-02-24 22:37:17,482 INFO  [pool-6-thread-1] reduce.MergeManagerImpl (MergeManagerImpl.java:finalMerge(667) ) - finalMerge called with 2 in-memory map-outputs and 0 on-disk map-outputs

2015-02-24 22:37:17,546 INFO  [pool-6-thread-1] mapred.Merger ( Merger.java:merge(591)) - Merging 2 sorted segments

2015-02-24 22:37:17,547 INFO  [pool-6-thread-1] mapred.Merger ( Merger.java:merge(690)) - Down to the last merge-pass, with 2 segments left of total size: 243 bytes

2015-02-24 22:37:17,555 INFO  [pool-6-thread-1] reduce.MergeManagerImpl (MergeManagerImpl.java:finalMerge(742) ) - Merged 2 segments, 257 bytes to disk to satisfy reduce memory limit

2015-02-24 22:37:17,556 INFO  [pool-6-thread-1] reduce.MergeManagerImpl (MergeManagerImpl.java:finalMerge(772) ) - Merging 1 files, 259 bytes from disk

2015-02-24 22:37:17,563 INFO  [pool-6-thread-1] reduce.MergeManagerImpl (MergeManagerImpl.java:finalMerge(787) ) - Merging 0 segments, 0 bytes from memory into reduce

2015-02-24 22:37:17,563 INFO  [pool-6-thread-1] mapred.Merger ( Merger.java:merge(591)) - Merging 1 sorted segments

2015-02-24 22:37:17,566 INFO  [pool-6-thread-1] mapred.Merger ( Merger.java:merge(690)) - Down to the last merge-pass, with 1 segments left of total size: 247 bytes

2015-02-24 22:37:17,568 INFO  [pool-6-thread-1] mapred.LocalJobRunner (LocalJobRunner.java:statusUpdate(591) ) - 2 / 2 copied.

2015-02-24 22:37:17,576 INFO  [main] mapreduce.Job ( Job.java:monitorAndPrintJob(1362) ) -  map 100% reduce 0%

2015-02-24 22:37:17,820 INFO  [pool-6-thread-1] Configuration.deprecation (Configuration.java:warnOnceIfDeprecated(1009) ) - mapred.skip.on is deprecated. Instead, use mapreduce.job.skiprecords

2015-02-24 22:37:18,045 INFO  [pool-6-thread-1] mapred.Task ( Task.java:done(995)) - Task:attempt_local1376201216_0001_r_000000_0 is done. And is in the process of committing

2015-02-24 22:37:18,049 INFO  [pool-6-thread-1] mapred.LocalJobRunner (LocalJobRunner.java:statusUpdate(591) ) - 2 / 2 copied.

2015-02-24 22:37:18,049 INFO  [pool-6-thread-1] mapred.Task ( Task.java:commit(1156)) - Task attempt_local1376201216_0001_r_000000_0 is allowed to commit now

2015-02-24 22:37:18,074 INFO  [pool-6-thread-1] output.FileOutputCommitter (FileOutputCommitter.java:commitTask(439) ) - Saved output of task ‘attempt_local1376201216_0001_r_000000_0‘ to hdfs://cloud01:9000/tmp/_temporary/0/task_local1376201216_0001_r_000000

2015-02-24 22:37:18,075 INFO  [pool-6-thread-1] mapred.LocalJobRunner (LocalJobRunner.java:statusUpdate(591) ) - reduce > reduce

2015-02-24 22:37:18,075 INFO  [pool-6-thread-1] mapred.Task ( Task.java:sendDone(1115)) - Task ‘attempt_local1376201216_0001_r_000000_0‘ done.

2015-02-24 22:37:18,076 INFO  [pool-6-thread-1] mapred.LocalJobRunner ( LocalJobRunner.java:run(325) ) - Finishing task: attempt_local1376201216_0001_r_000000_0

2015-02-24 22:37:18,076 INFO  [Thread-14] mapred.LocalJobRunner ( LocalJobRunner.java:runTasks(456) ) - reduce task executor complete.

2015-02-24 22:37:18,578 INFO  [main] mapreduce.Job ( Job.java:monitorAndPrintJob(1362) ) -  map 100% reduce 100%

2015-02-24 22:37:18,578 INFO  [main] mapreduce.Job ( Job.java:monitorAndPrintJob(1373) ) - Job job_local1376201216_0001 completed successfully

2015-02-24 22:37:18,590 INFO  [main] mapreduce.Job ( Job.java:monitorAndPrintJob(1380) ) - Counters: 38