java - 在Hadoop中执行wordcount程序时出错

Question

我正在尝试在Eclipse中为hadoop执行WordCount程序，并且出现以下错误:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at WordCount.run(WordCount.java:22)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
at WordCount.main(WordCount.java:35)

我已经从互联网复制了代码，该代码看起来不错，但是为了引用，我将代码粘贴在这里:

WordCount.java

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;

public class WordCount extends Configured implements Tool{
      public int run(String[] args) throws Exception
      {
        //creating a JobConf object and assigning a job name for     identification purposes
        JobConf conf = new JobConf(getConf(), WordCount.class);
        conf.setJobName("WordCount");

        //Setting configuration object with the Data Type of output Key   and Value
        conf.setOutputKeyClass(Text.class);
        conf.setOutputValueClass(IntWritable.class);

        //Providing the mapper and reducer class names
        conf.setMapperClass(WordCountMapper.class);
        conf.setReducerClass(WordCountReducer.class);
        //We wil give 2 arguments at the run time, one in input path and other is output path
        Path inp = new Path(args[0]);
        Path out = new Path(args[1]);
        //the hdfs input and output directory to be fetched from the command line
        FileInputFormat.addInputPath(conf, inp);
        FileOutputFormat.setOutputPath(conf, out);

        JobClient.runJob(conf);
        return 0;
  }

  public static void main(String[] args) throws Exception
  {
        // this main function will call run method defined above.
    int res = ToolRunner.run(new Configuration(), new WordCount(),args);
        System.exit(res);
  }

}

Answer 1

似乎您没有传递正确的命令行参数。