以下是使用AWS Hadoop MapReduce解决Word Count Average问题的示例代码：

Mapper类：

import java.io.IOException;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;

public class WordCountMapper extends Mapper {

    private final static IntWritable one = new IntWritable(1);
    private Text word = new Text();

    public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
        String[] words = value.toString().split(" ");
        for (String word : words) {
            this.word.set(word);
            context.write(this.word, one);
        }
    }
}

Reducer类：

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

public class WordCountReducer extends Reducer {

    private IntWritable result = new IntWritable();

    public void reduce(Text key, Iterable values, Context context)
            throws IOException, InterruptedException {
        int sum = 0;
        int count = 0;
        for (IntWritable value : values) {
            sum += value.get();
            count++;
        }
        int average = sum / count;
        result.set(average);
        context.write(key, result);
    }
}

Driver类：

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.output.FileOutputFormat;

public class WordCountAverage {

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        Job job = Job.getInstance(conf, "word count average");
        job.setJarByClass(WordCountAverage.class);
        job.setMapperClass(WordCountMapper.class);
        job.setCombinerClass(WordCountReducer.class);
        job.setReducerClass(WordCountReducer.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);
        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}

请注意，上述代码仅为示例，您需要根据您的实际需求进行适当的更改和配置。此示例假定输入文件中的每个单词以空格分隔，并且每个单词都位于单独的行中。