【算法-字符串】统计一个字符串中字符出现的次数，按照出现次数升序排序，如果出现次数相同则按照字典顺序，如果有大写则大写出现在小写之后

public class Main {public static void main(String[] args) {HashMap<Character, Integer> hashMap = new HashMap();Scanner scanner = new Scanner(System.in);String input = scanner.nextLine();// 字符串转字符数组char[] chars = input.toCharArray();// 遍历字符数组，统计字符数组中每个字符出现的次数for (char c : chars) {if (hashMap.containsKey(c)) {hashMap.put(c, hashMap.get(c)+1);} else {hashMap.put(c, 1);}}ArrayList<Map.Entry<Character, Integer>> list = new ArrayList<>();list.addAll(hashMap.entrySet());ValueComparator vc = new ValueComparator();Collections.sort(list, vc);for (int i = 0; i < list.size(); i++) {System.out.print(list.get(i).getKey() + ":" + list.get(i).getValue() + ";");}}/*** 按照字符出现的次数升序排序，如果出现次数相同则按照字典顺序，如果有大写则大写出现在小写之后*/private static class ValueComparator implements Comparator<Map.Entry<Character, Integer>> {@Overridepublic int compare(Map.Entry<Character, Integer> m, Map.Entry<Character, Integer> n) {//首先是按照 value 值来进行比较int v = n.getValue() - m.getValue();if (v == 0) {// 如果value值相同则按照key的值进行比较// 如果都是大写字母或小写字母按照字典顺序if ((!Character.isUpperCase(m.getKey()) && !Character.isUpperCase(n.getKey())) ||(Character.isUpperCase(m.getKey()) && Character.isUpperCase(n.getKey()))) {return m.getKey() - n.getKey();} else {//如果有大写和小写，则小写在前，大写在后return n.getKey() - m.getKey();}} else {return v;}}}
}