我试着用这个解决方案对我的减速机的输出进行排序 Hadoop 如本问题所述：
mapreduce按值降序排序
这一个和java8有一些冲突，所以我解决了如下问题：

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

import java.util.Map;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.LinkedHashMap;
import java.util.Collections;
import java.util.List;
import java.util.Comparator;

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

    private IntWritable result = new IntWritable();
    public Map<String , Integer> map = new LinkedHashMap<String , Integer>();

    public void reduce(Text key, Iterable<IntWritable> values, Context context)
    throws IOException, InterruptedException {

        int sum = 0;
        for (IntWritable value : values) {
            sum += value.get();
        }
        map.put(key.toString() , sum);

        result.set(sum);
        context.write(key, result);
    }

    public void cleanup(Context context){
        //Cleanup is called once at the end to finish off anything for reducer
        //Here we will write our final output
        Map<String , Integer>  sortedMap = new HashMap<String , Integer>();
        sortedMap = sortMap(map);

        for (Map.Entry<String,Integer> entry : sortedMap.entrySet()){
            context.write(new Text(entry.getKey()),new IntWritable(entry.getValue()));
        }
    }

    public Map<String , Integer > sortMap (Map<String,Integer> unsortMap){

        Map<String ,Integer> hashmap = new HashMap<String,Integer>();
        int count=0;
        List<Map.Entry<String,Integer>> list = new LinkedList<Map.Entry<String,Integer>>(unsortMap.entrySet());
        //Sorting the list we created from unsorted Map
        Collections.sort(list , new Comparator<Map.Entry<String,Integer>>(){
            public int compare (Map.Entry<String , Integer> o1 , Map.Entry<String , Integer> o2 ){
                //sorting in descending order
                return o2.getValue().compareTo(o1.getValue());
            }
        });

        for(Map.Entry<String, Integer> entry : list){
            // only writing top 3 in the sorted map
            // if(count>2)
            // break;
            hashmap.put(entry.getKey(),entry.getValue());
        }

        return hashmap ;
    }

}

问题是在运行作业后，输出没有排序：

11  1041557
14  1304166
17  1434978
2   733462
20  1288767
23  1677571
5   460629
8   497403
11  1041557
23  1677571
2   733462
14  1304166
5   460629
17  1434978
8   497403
20  1288767

怎么解决？