使用Collections工具类对List集合进行排序

List<Map<String, Object>> list = new ArrayList<>();
for (int i = 1; i <= 4; i++) {
    Map<String, Object> map = new HashMap<>();
    map.put("age", 9 + i);
    list.add(map);
}
List<Map<String, Object>> age = sort(list, "age");
for (Map<String, Object> map : age) {
    System.out.print(map.get("age")+"============");
    System.out.println(map.get("rank"));
}

public static List<Map<String, Object>> sort(List<Map<String, Object>> list, String param) {
        Collections.sort(list, new Comparator<Map<String, Object>>() {
        @Override
        public int compare(Map<String, Object> o1, Map<String, Object> o2) {
            if ((Integer) o1.get(param) > (Integer) o2.get(param)) {
                return -1;
            } else if ((Integer) o1.get(param) < (Integer) o2.get(param)) {
                return 1;
            } else {
                return 0;
            }
        }
    });
    if (null != list && list.size() > 0) {
        for (int i = 0; i < list.size(); i++) {
            if(null!=list.get(i)) {
                list.get(i).put("rank", i+1);
            }
        }
    }
    return list;
}
结果：

13============1
12============2
11============3
10============4