比较

public static String generateMd5Key(int dishId, List<GroupItem> groupItemList) {    Collections.sort(groupItemList, new Comparator<GroupItem>() {        public int compare(GroupItem arg0, GroupItem arg1) {            return arg0.getgId() - (arg1.getgId());        }    });    for (int j = 0; j < groupItemList.size(); j++) {        GroupItem groupItem = groupItemList.get(j);        List<Integer> sIdList = groupItem.getsIdList();        Collections.sort(sIdList);    }    return SignUtils.MD5(dishId + String.valueOf(JSON.toJSON(groupItemList)));}