Java 中List＜Map＜String,String＞＞排序问题

public static void mapSorts(List> map) {
    Collections.sort(map, new Comparator>() {

        @Override
        public int compare(Map o1, Map o2) {
            // TODO Auto-generated method stub
            if (Double.parseDouble(o1.get("sumall").toString())>Double.parseDouble(o2.get("sumall").toString()) ) {
                return -1;
            }
            return 1;
        }
    });
}