Java 统计字符串中的每个字符出现的次数

import java.util.*;

/*
    计算字符串中每个字符出现的次数
    1.toCharArray()方法，变成字符数组，遍历数组统计每个字符出现的个数
    2.String类length(), CharAt()
 */
public class Map_Exercise {
          
   
    public static void main(String[] args) {
          
   
        Scanner scanner = new Scanner(System.in);
        String s = scanner.next();
       char[] c = s.toCharArray();
        Map<Character,Integer> map = new HashMap<>();
        for (char c1 : c) {
          
   
            if(map.containsKey(c1))
                map.put(c1,map.get(c1)+1);
            else {
          
   
                map.put(c1,1);
            }
        }
        Set<Map.Entry<Character, Integer>> set = map.entrySet();
        for (Map.Entry<Character, Integer> characterIntegerEntry : set) {
          
   
            System.out.println(characterIntegerEntry.getKey()+"出现的次数是："+characterIntegerEntry.getValue());
        }
        scanner.close();
    }
}