Question

执行命令时

hadoop jar /home/edureka/Desktop/invertedindex.jar hdfs:/hdfs/inverted  hdfs:/hdfs/invertedout

我收到以下错误
任何人都可以帮我修复代码

线程中的异常＆＃34; main＆＃34; java.lang.ClassNotFoundException：hdfs：.hdfs.inverted 在java.net.URLClassLoader $ 1.run（URLClassLoader.java:366）在java.net.URLClassLoader $ 1.run（URLClassLoader.java:355） at java.security.AccessController.doPrivileged（Native Method）在java.net.URLClassLoader.findClass（URLClassLoader.java:354） at java.lang.ClassLoader.loadClass（ClassLoader.java:425） at java.lang.ClassLoader.loadClass（ClassLoader.java:358） at java.lang.Class.forName0（Native Method）在java.lang.Class.forName（Class.java:270）在org.apache.hadoop.util.RunJar.main（RunJar.java:205）

我尝试了所有先决条件但仍面临问题。enter code here

以下是代码：

import java.io.IOException;
import java.util.HashMap;

import org.apache.hadoop.conf.Configuration;
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.Mapper;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.mapreduce.Reducer;

public class InvertedIndex {

    public static class Map extends Mapper<LongWritable,Text,Text,Text> {


        @Override
        public void map(LongWritable key, Text value, Context context)
        throws IOException,InterruptedException
        {   

            String fileName = ((FileSplit) context.getInputSplit()).getPath().getName();
            String line=value.toString();
            String words[]=line.split(" ");
            for(String s:words){
                context.write(new Text(s), new Text(fileName));
            }


        }
    }

    public static class Reduce extends
    Reducer<Text, Text, Text, Text> {



      @Override
      public void reduce(Text key, Iterable<Text> values, Context context)
        throws IOException, InterruptedException {
         HashMap m=new HashMap();
         int count=0;
          for(Text t:values){
              String str=t.toString();
              if(m!=null &&m.get(str)!=null){
                  count=(int)m.get(str);
                  m.put(str, ++count);
              }else{`enter code here`
                  m.put(str, 1);    
              }
          }
          context.write(key, new Text(m.toString()));
        }
    }


    public static void main(String[] args) throws Exception { 

        Configuration conf= new Configuration();

        Job job = new Job(conf,"UseCase1");


        //Defining the output value class for the mapper
        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(Text.class);
        job.setJarByClass(InvertedIndex.class);
        job.setMapperClass(Map.class);
        job.setReducerClass(Reduce.class);

        //Defining the output value class for the mapper
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);
        job.setInputFormatClass(TextInputFormat.class);
        job.setOutputFormatClass(TextOutputFormat.class);

        Path outputPath = new Path(args[1]);

        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, outputPath);

            //deleting the output path automatically from hdfs so that we don't have delete it explicitly

        outputPath.getFileSystem(conf).delete(outputPath);

            //exiting the job only if the flag value becomes false

        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}

Answer 1

您需要在hadoop jar命令中传递Main类，如文档中所述。

你的命令

hadoop jar /home/edureka/Desktop/invertedindex.jar hdfs：/ hdfs / inverted HDFS：/ HDFS / invertedout

应该是

hadoop jar /home/edureka/Desktop/invertedindex.jar InvertedIndex hdfs：/ hdfs / inverted hdfs：/ hdfs / invertedout

另外

job.setJarByClass（InvertedIndex.class）;

应该是

job.setJarByClass（倒排索引）;

代替。

我刚刚进行了类似的讨论here。

Answer 2

hadoop命令应该知道在jar参数后正在执行哪个类：

Usage: hadoop jar <jar> [mainClass] args... - see manual

所以你应该运行jar as：

hadoop jar /home/edureka/Desktop/invertedindex.jar InvertedIndex hdfs:/hdfs/inverted  hdfs:/hdfs/invertedout

工作配置看起来不错。不要对job.setJarbyClass：see Class-Job

进行任何更改

线程＆＃34; main＆＃34;中的例外情况java.lang.ClassNotFoundException：hdfs：.hdfs.inverted

2 个答案: