java getCredentials方法在试图通过导入所有JAR文件在eclipse中运行“单词计数”程序时出错

8 月，2 周 Questions & Answers 904

错误：线程“main”java中出现异常。lang.NoSuchMethodError:org。阿帕奇。hadoop。安全用户组信息。getCredentials（）Lorg/apache/hadoop/security/Credentials；在org。阿帕奇。hadoop。mapreduce。工作（Job.java:135）在org。阿帕奇。hadoop。mapreduce。工作getInstance（Job.java:176）在org。阿帕奇。hadoop。mapreduce。工作getInstance（Job.java:195）在WordCount。main（WordCount.java:20）

Hadoop 2.2.0版

字数。java

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.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 void main(String[] args) throws Exception {
        if (args.length != 2) {
          System.out.println("usage: [input] [output]");
          System.exit(-1);
        }


        Job job = Job.getInstance(new Configuration(), "word count");
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);

        job.setMapperClass(WordMapper.class); 
        job.setReducerClass(SumReducer.class);  

        job.setInputFormatClass(TextInputFormat.class);
        job.setOutputFormatClass(TextOutputFormat.class);

        FileInputFormat.setInputPaths(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));

        job.setJarByClass(WordCount.class);
        job.setJobName("WordCount");

        job.submit();






 }
}

WordMapper。java

import java.io.IOException;    
import java.util.StringTokenizer;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
public class WordMapper extends Mapper<Object, Text, Text, IntWritable> {
private Text word = new Text();
private final static IntWritable one = new IntWritable(1);
 @Override
        public void map(Object key, Text value,
        Context contex) throws IOException, InterruptedException {
        // Break line into words for processing
        StringTokenizer wordList = new StringTokenizer(value.toString());
        while (wordList.hasMoreTokens()) {
       word.set(wordList.nextToken());
       contex.write(word, one);
      }
     }
    }

summer。java

import java.io.IOException;
import java.util.Iterator;

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



public class SumReducer extends Reducer<Text, IntWritable, Text, IntWritable> {

 private IntWritable totalWordCount = new IntWritable();

 @Override
 public void reduce(Text key, Iterable<IntWritable> values, Context context)
            throws IOException, InterruptedException {
  int wordCount = 0;
  Iterator<IntWritable> it=values.iterator();
  while (it.hasNext()) {
   wordCount += it.next().get();
  }
  totalWordCount.set(wordCount);
  context.write(key, totalWordCount);
 }
}

请告诉我能做什么？该程序使用了最新的mapreduce API。hadoop 2.2.0附带的所有JAR也被导入eclipse中

谢谢：）

Python中文网

有 Java 编程相关的问题?

java getCredentials方法在试图通过导入所有JAR文件在eclipse中运行“单词计数”程序时出错

共 (1) 个答案

# 1 楼答案