查找一个字符串中各个字符出现的次数，用TreeMap实现

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这是一道常见的算法题。利用TreeMap实现

import java.util.HashMap;import java.util.Iterator;import java.util.Map.Entry;public class CharOcurNum {public static void main(String[] args) {String str = "adfadfajgagka}}}jg**dkja";HashMap<Character,Integer> hashmap = ocurNum(str);Iterator<Entry<Character, Integer>> it=hashmap.entrySet().iterator();while(it.hasNext()){Entry<Character, Integer> entry=it.next();char key=entry.getKey();int value=entry.getValue();System.out.println(key+"..."+value);}}private static HashMap<Character,Integer> ocurNum(String str) {// TODO Auto-generated method stubHashMap<Character, Integer> hashmap = new HashMap<Character, Integer>();char[] s=str.toCharArray();for(int i=0;i<s.length;i++){Integer value=hashmap.get(s[i]);if(value==null){hashmap.put(s[i],1);}else{hashmap.put(s[i], value+1);}}return hashmap;}}

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