Hadoop 2.2.0 的 map reduce 示例出错

Question

我是 hadoop 新手，在安装 Hadoop 2.2.0 后，我尝试按照示例 http://www.srccodes.com/p/article/45/run-hadoop-wordcount-mapreduce-example-windows 尝试一个简单的 map reduce 作业。

但是，每当我尝试对我创建的 txt 文件执行 map reduce 作业时，我都会收到此消息的失败

c:\hadoop>bin\yarn jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.2.0.ja
r wordcount /input output
14/03/26 14:20:48 INFO client.RMProxy: Connecting to ResourceManager at /0.0.0.0
:8032
14/03/26 14:20:50 INFO input.FileInputFormat: Total input paths to process : 1
14/03/26 14:20:51 INFO mapreduce.JobSubmitter: number of splits:1
14/03/26 14:20:51 INFO Configuration.deprecation: user.name is deprecated. Inste
ad, use mapreduce.job.user.name
14/03/26 14:20:51 INFO Configuration.deprecation: mapred.jar is deprecated. Inst
ead, use mapreduce.job.jar
14/03/26 14:20:51 INFO Configuration.deprecation: mapred.output.value.class is d
eprecated. Instead, use mapreduce.job.output.value.class
14/03/26 14:20:51 INFO Configuration.deprecation: mapreduce.combine.class is dep
recated. Instead, use mapreduce.job.combine.class
14/03/26 14:20:51 INFO Configuration.deprecation: mapreduce.map.class is depreca
ted. Instead, use mapreduce.job.map.class
14/03/26 14:20:51 INFO Configuration.deprecation: mapred.job.name is deprecated.
 Instead, use mapreduce.job.name
14/03/26 14:20:51 INFO Configuration.deprecation: mapreduce.reduce.class is depr
ecated. Instead, use mapreduce.job.reduce.class
14/03/26 14:20:51 INFO Configuration.deprecation: mapred.input.dir is deprecated
. Instead, use mapreduce.input.fileinputformat.inputdir
14/03/26 14:20:51 INFO Configuration.deprecation: mapred.output.dir is deprecate
d. Instead, use mapreduce.output.fileoutputformat.outputdir
14/03/26 14:20:51 INFO Configuration.deprecation: mapred.map.tasks is deprecated
. Instead, use mapreduce.job.maps
14/03/26 14:20:51 INFO Configuration.deprecation: mapred.output.key.class is dep
recated. Instead, use mapreduce.job.output.key.class
14/03/26 14:20:51 INFO Configuration.deprecation: mapred.working.dir is deprecat
ed. Instead, use mapreduce.job.working.dir
14/03/26 14:20:51 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_13
95833928952_0004
14/03/26 14:20:52 INFO impl.YarnClientImpl: Submitted application application_13
95833928952_0004 to ResourceManager at /0.0.0.0:8032
14/03/26 14:20:52 INFO mapreduce.Job: The url to track the job: http://GoncaloPe
reira:8088/proxy/application_1395833928952_0004/
14/03/26 14:20:52 INFO mapreduce.Job: Running job: job_1395833928952_0004
14/03/26 14:21:08 INFO mapreduce.Job: Job job_1395833928952_0004 running in uber
 mode : false
14/03/26 14:21:08 INFO mapreduce.Job:  map 0% reduce 0%
14/03/26 14:21:20 INFO mapreduce.Job: Task Id : attempt_1395833928952_0004_m_000
000_0, Status : FAILED
Error: java.lang.ClassCastException: org.apache.hadoop.mapreduce.lib.input.FileS
plit cannot be cast to org.apache.hadoop.mapred.InputSplit
        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:402)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:341)
        at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:415)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInforma
tion.java:1491)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:157)
14/03/26 14:21:33 INFO mapreduce.Job: Task Id : attempt_1395833928952_0004_m_000
000_1, Status : FAILED
Error: java.lang.ClassCastException: org.apache.hadoop.mapreduce.lib.input.FileS
plit cannot be cast to org.apache.hadoop.mapred.InputSplit
        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:402)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:341)
        at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:415)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInforma
tion.java:1491)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:157)
14/03/26 14:21:48 INFO mapreduce.Job: Task Id : attempt_1395833928952_0004_m_000
000_2, Status : FAILED
Error: java.lang.ClassCastException: org.apache.hadoop.mapreduce.lib.input.FileS
plit cannot be cast to org.apache.hadoop.mapred.InputSplit
        at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:402)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:341)
        at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:415)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInforma
tion.java:1491)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:157)
14/03/26 14:22:04 INFO mapreduce.Job:  map 100% reduce 100%
14/03/26 14:22:10 INFO mapreduce.Job: Job job_1395833928952_0004 failed with sta
te FAILED due to: Task failed task_1395833928952_0004_m_000000
Job failed as tasks failed. failedMaps:1 failedReduces:0
14/03/26 14:22:10 INFO mapreduce.Job: Counters: 6
        Job Counters
                Failed map tasks=4
                Launched map tasks=4
                Other local map tasks=3
                Data-local map tasks=1
                Total time spent by all maps in occupied slots (ms)=48786
                Total time spent by all reduces in occupied slots (ms)=0

由于我一步一步地跟踪一切，没有任何问题，我不知道为什么会这样，有人知道吗？

编辑：尝试采用 2.3.0 与给出的示例 jar 相同的问题，我尝试编译下面的代码，不知道问题是什么

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 teste {

   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.setJarByClass(teste.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);
   }

}

Answer 1

我遇到了同样的问题 (java.lang.ClassCastException)，并且能够通过以管理员权限运行 Hadoop 来解决它。问题似乎是符号链接的创建，默认情况下非管理员 Windows 用户无法创建。以管理员身份打开控制台，然后按照链接中的示例中所述继续操作。

Answer 2

您提供的链接将输入参数作为输入而不是 /input...尝试使用此语法...

C:\hadoop>bin\yarn jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.2.0.jar wordcount input output

如果这不起作用，请查看这个 - Link 并修改映射器类。