【学习】自定义排序-枚举定义实现

谁借莪１个温暖的怀抱￠ 2022-10-23 12:43 302阅读 0赞

# 自定义排序-枚举实现 #

1.  实体(重点Comparable参数)

@Data
    @EqualsAndHashCode(callSuper = false)
    public class StatisticViewVo extends BaseEntity { 
    
        /** * 商品ID */
        @Field("goods_id")
        private Integer goodsId;
        /** * 商品名称 */
        @Field("goods_name")
        private String goodsName;
    
        /** * 货 号 */
        @Field("spec_no")
        private String specNo;
    
        /** * 人 气 */
        @Field("hot_num")
        private Integer hotNum;
    
        /** * 商品价格 */
        private BigDecimal price;
    
        public enum FieldEnum { 
            /** */
            goodsId(StatisticViewVo::getGoodsId),
            hotNum(StatisticViewVo::getHotNum),
            goodsName(StatisticViewVo::getGoodsName),
            specNo(StatisticViewVo::getSpecNo),
            price(StatisticViewVo::getPrice);
    
            public Function<StatisticViewVo, Comparable> fun;
    
            FieldEnum(Function<StatisticViewVo, Comparable> fun) { 
                this.fun = fun;
            }
    
            public Comparator sort(Sort s) { 
                return Sort.DESC.equals(s) ? Comparator.comparing(fun) : Comparator.comparing(fun).reversed();
            }
    
        }
    
        public enum Sort { 
            /** 排序 */
            ASC, DESC
        }
    }

1.  业务实现排序写法

// originTotalList是数据库获取的数据（例如mongodb查询得到）
    // statisticDto.getColumnName()为用户页面选择要排序的字段
    // statisticDto.getCollectValue()为升序或降序 ASC DESC
    StatisticViewVo.FieldEnum fileEnum = StatisticViewVo.FieldEnum.valueOf(statisticDto.getColumnName());
            Comparator<StatisticViewVo> sort = fileEnum.sort(StatisticViewVo.Sort.valueOf(statisticDto.getCollectValue()));
    
            List totalList = (List) originTotalList.stream().sorted(sort).collect(Collectors.toList());
            // 排序完成列表totalList