java 实现单词计数.top N

思路

1. 先统计每个单词出现的个数
2. 利用 TreeSet 的自动排序的功能

上代码

1. wordcount

public void wordCount() {        String route = "青岛路 青岛路 济阳路口东 济南路 宴坡路 ";        Map<String, Integer> map = new HashMap<String, Integer>();        StringTokenizer st = new StringTokenizer(route, " ");        while (st.hasMoreTokens()) {            String letter = st.nextToken();            int count;            if (map.get(letter) == null) {                count = 1;            } else {                count = map.get(letter).intValue() + 1;            }            map.put(letter, count);        }        Set<StationEntity> set = new TreeSet<StationEntity>();        for (String word : map.keySet()) {            set.add(new StationEntity(word, map.get(word)));            System.out.println("word" + word + ":" + map.get(word));        }        System.out.println(" 输出形式 --");        for (Iterator<StationEntity> it = set.iterator(); it.hasNext(); ) {            StationEntity station = it.next();            System.out.println(station.getName() + "=" + station.getCount());          System.out.println("station"+station+":");        }    }

2.StationEntity

package com.dk.route;/** * Created by zzy on 15/11/28. */public class StationEntity implements Comparable<StationEntity>{    private String name ;    public int getCount() {        return count;    }    public void setCount(int count) {        this.count = count;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    private int  count;    public StationEntity(String name,int  count){        this.name = name;        this.count = count;    }    public int compareTo(StationEntity o) {        int cmp = count - o.count;        StationEntity s = (StationEntity)o ;        return cmp ==0 ?name.compareTo(o.name):-cmp;    }}

3.运行结果