对list里的数据进行大小的排序

// 对充值金额进行排序            Collections.sort(rule, new Comparator<MemberSubRuleListBean>() {                @Override                public int compare(MemberSubRuleListBean o1, MemberSubRuleListBean o2) {                    if (o1.getRechargeAmount().compareTo(o2.getRechargeAmount()) == 0) {                        return 0;                    } else if (o1.getRechargeAmount().compareTo(o2.getRechargeAmount()) > 0) {                        return 1;                    } else {                        return -1;                    }                }            });

为什么返回0,1，-1就能排序，以后再更新