算法求解String str = "A,B,C,A,B,A"解决办法

    public static void main(String[] args) {        String str = "A,B,C,A,B,A";        Map<String, Integer> tm = new TreeMap<String, Integer>();        String[] words = str.split(",");                for (final String s : words) {            if (!s.isEmpty()) {                if (!tm.containsKey(s)) {                    tm.put(s, 1);                } else {                    tm.put(s, tm.get(s).intValue() + 1);                }                            }        }        for (Map.Entry<String, Integer> entry : tm.entrySet()) {            System.out.println(entry.getKey() + ":" + entry.getValue());        }    }