如何用java语言实现遍历字符串中每个字符出现的次数

 遍历字符串中adaccvbvnmtmabdklelracuk每个字符出现的次数

package com.zuoye;import java.util.Map;import java.util.Set;import java.util.TreeMap;public class ArrayDemo {/** *  遍历字符串中adaccvbvnmtmabdklelracuk每个字符出现的次数 *   */public static void main(String[] args) { String str="adaccvbvnmtmabdklelracuk"; char[] ch=str.toCharArray(); TreeMap<Character, Integer> map=new TreeMap<Character, Integer>(); for(char c:ch){ Integer sum=map.get(c); if(sum==null){ map.put(c, 1); }else{ map.put(c,++sum); } }        StringBuilder sb=new StringBuilder();        Set<Character> set=map.keySet();        for(Character c:set){        sb.append(c).append(":").append(map.get(c)).append(",");        }        System.out.println("结果是："+sb.toString());}}