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 map=new TreeMap();
		 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 set=map.keySet();
        for(Character c:set){
        	sb.append(c).append(":").append(map.get(c)).append(",");
        }
        System.out.println("结果是："+sb.toString());
	}

}