TreeSet按value排序

今天学习到TreeSet，但是它是按照key的值来排序的，那如果我们想要按照value的值排序呢？这个问题我上网看了好久，终于找到一个比较易懂的例子：

例：（统计输入数字的个数）

话不多说，看代码就懂

import java.util.*;
import java.util.Scanner;

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

    HashMap<Integer, Integer> hashMap = new HashMap<Integer,Integer>();
	Scanner input = new Scanner(System.in);
	int num = input.nextInt();
    while (num != 0) 
	{
		if(hashMap.get(num) == null)
		{
		  hashMap.put(num,1);
		}
		else
		{
			int value = hashMap.get(num).intValue();
			value++;
			hashMap.put(num,value);
		}
		num = input.nextInt();
	}

    // Create a tree map from the hash map
    TreeMap<Integer, Integer> treeMap =
      new TreeMap<Integer, Integer>(hashMap);

	Set<Map.Entry<Integer,Integer>> entrySet = treeMap.entrySet();

	ArrayList<Count> list = new ArrayList<Count>();
	for(Map.Entry<Integer,Integer> entry:entrySet){
		Count cc = new Count(entry.getKey(),entry.getValue());
		list.add(cc);
	}
	Collections.sort(list);
/*
	for(int i = 0; i< list.size();i++){
		System.out.println(list.get(i).getKey() + "\t" + list.get(i).getValue());
	}
*/

//找出多个最大值
	int i = 0;
	for(; i< list.size()-1;i++){
		if(list.get(i).getValue() > list.get(i+1).getValue())
		{
			System.out.println(list.get(i).getKey() + "\t" + list.get(i).getValue());
			break;
		}
		else if(list.get(i).getValue() == list.get(i+1).getValue() && i+1 < list.size())
		{
			System.out.println(list.get(i).getKey() + "\t" + list.get(i).getValue());

		}
	}
	if(i == list.size() -1 )
		System.out.println(list.get(i).getKey() + "\t" + list.get(i).getValue());

  }
}

class Count implements Comparable {
  int key;
  int value;

  public int getKey(){
	  return key;
  }
  public int getValue(){
	  return value;
  }
  public Count(int key, int value) {
    this.key = key;
    this.value = value;
  }

  public int compareTo(Object o) {
    return -(value - ((Count)o).value);
  }

  public boolean equals(Object o) {
    return value == ((Count)o).value;
  }
}