【java】用HashMap计数，用TreeSet排序

 package com.tn.hashMap;

 import java.util.HashMap;
 import java.util.TreeSet;

 public class HashMapDemo {
     public static void main(String[] args){

         String str="eeeeaccbbddddffffff";
         HashMap<String,Integer> hashMap=new HashMap<String,Integer>();
         for(int i=0;i<str.length();i++){
             if(!hashMap.containsKey(str.substring(i, i+1))){
                 hashMap.put(str.substring(i, i+1), 1);
             }else{
                 hashMap.put(str.substring(i,i+1), hashMap.get(str.substring(i, i+1))+1);
             }
         }

         TreeSet<T> treeSet=new TreeSet<T>();
         for(String key:hashMap.keySet()){
             T t=new T(key,hashMap.get(key));
             treeSet.add(t);
         }
         System.out.println(treeSet);
     }
 }

 class T implements Comparable<T>{
     private String value;
     private Integer count;

     public T(String value, Integer count) {
         super();
         this.value = value;
         this.count = count;
     }

     public String getValue() {
         return value;
     }

     public void setValue(String value) {
         this.value = value;
     }

     public Integer getCount() {
         return count;
     }

     public void setCount(Integer count) {
         this.count = count;
     }

     @Override
     public String toString() {
         return value+"出现"+count+"次。";
     }

     @Override
     public int compareTo(T o) {
         if(this.count!=o.count)
             return this.count-o.count;//以出现次数排序
         else
             return this.value.compareTo(o.value);//出现次数相同以字母顺序排序
     }

 }