运行Map reduce程序时出现错误java.lang.RuntimeException:java.lang.ClassNotFoundException:wordcount\u classes.wordcount$Map

我是Hadoop新手，尝试运行Map reduce程序，即Word Count，我得到以下错误java.lang.RuntimeException:java.lang.ClassNotFoundException:wordcount\u classes.wordcount$Map和WordCount.java

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 WordCount {

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.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.setJarByClass(WordCount.class);    
   job.waitForCompletion(true);
}

}

我正在按照命令编译程序

hadoop jar wordcount_classes/wordcount.jar wordcount_classes/WordCount input r1

 hadoop jar <path_to_jar>/wordcount.jar WordCount <hdfs_path_to_input>/input <hdfpath>/r1

---

请检查以下内容：

您是否编译为可运行jar

您是否从jar包含的文件夹运行 或

使用以下命令运行

hadoop jar wordcount_classes/wordcount.jar wordcount_classes/WordCount input r1

 hadoop jar <path_to_jar>/wordcount.jar WordCount <hdfs_path_to_input>/input <hdfpath>/r1

hadoop jar/wordcount.jar wordcount/input/r1

---

这些输入和输出目录应该位于hdfs文件或其他地方的何处？输入应该是位于hdfs中的输入源文件，输出应该是hdfs中的目录，但不应创建，输出将由程序本身创建。请告诉我您的问题是否已解决我如何知道在hdfs中创建的目录的文件系统路径？WordCount.class文件应该在哪里？它应该只在hdfs文件系统中吗？不需要在hdfs中，它可以在本地系统中