案例题：计算一个字符串中每个字符出现的次数

案例分析图：

 代码：

  public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("输入一个字符串");
        String next = sc.nextLine();

        char[] chars = next.toCharArray();
        Arrays.sort(chars);

        HashMap<Character, Integer> map = new HashMap<>();
        for (char aChar : chars) {
            if (map.containsKey(aChar)) {
                Integer value = map.get(aChar);
                value++;
                map.put(aChar,value);
            }else{
                map.put(aChar,1);
            }
        }
        System.out.println(map);
    }

运行结果：

    Scanner sc = new Scanner(System.in);
System.out.println("输入一个字符串");
String next = sc.nextLine();

    char[] chars = next.toCharArray();
Arrays.sort(chars);

HashMap<Character, Integer> map = new HashMap<>();
    for (char aChar : chars) {
        if (map.containsKey(aChar)) {
            Integer value = map.get(aChar);
value++;
map.put(aChar,value);
}else{
            map.put(aChar,1);
}
    }
    System.out.println(map);
}