【如何在实现保存排序的需求同时保证逻辑上不会出错】

    //保存排序
    @RequestMapping(value = "/UpdateOrderBy",method = RequestMethod.POST)
    public CodeMessageDate updateOrderBy(@RequestBody List<WorkCollection> workCollections){
        if(null==workCollections||workCollections.size()==0){
            return new CodeMessageDate(0,"无传入数据");
        }else{
            List<WorkCollection> listBackup = new ArrayList<>();
            List<WorkCollection> list = new ArrayList<>();
            for(WorkCollection collection:workCollections){
                WorkCollection workCollectionBackup = new WorkCollection();
                WorkCollection workCollection = new WorkCollection();
                workCollection.setCollectionId(collection.getCollectionId());
                if(null==workCollectionService.selectCollection(workCollection)){
                    return new CodeMessageDate(0,"未找到该条数据",workCollection);
                }else if(null==collection.getCollectionOrderBy()||collection.getCollectionOrderBy()<=0) {
                    return new CodeMessageDate(0, "未找到排序数据",workCollection);
                }else {
                    workCollectionBackup.setCollectionId(workCollectionService.selectCollection(workCollection).getCollectionId());
                    workCollectionBackup.setCollectionOrderBy(workCollectionService.selectCollection(workCollection).getCollectionOrderBy());
                    listBackup.add(workCollectionBackup);
                    workCollection.setCollectionOrderBy(collection.getCollectionOrderBy());
                    list.add(workCollection);
                }
            }
            workCollectionService.updateOrderBy(list);
            if (null==workCollectionService.selectCollectionOrderBy()||workCollectionService.selectCollectionOrderBy().size()==0){
                return new CodeMessageDate(1,"保存排序成功");
            }else{
                workCollectionService.updateOrderBy(listBackup);
                return new CodeMessageDate(0,"排序数据错误，操作已回退");
            }

        }

    //保存排序
    int updateOrderBy(@Param(value = "list")List<WorkCollection> list);

    <!--倒叙排序作品集order_by-->
    <select id="selectCollectionOrder" resultMap="workCollectionMap">
        select collection_order_by from work_collection order by collection_order_by desc
    </select>
    <!--循环遍历批量保存排序-->
    <update id="updateOrderBy" parameterType="java.util.List">
        <foreach collection="list" item="workCollection" separator=";">
            update work_collection set collection_order_by=#{workCollection.collectionOrderBy} where collection_id=#{workCollection.collectionId}
        </foreach>
    </update>
    <!--通过作品集Id查询作品集信息-->
    <select id="selectCollection" resultMap="workCollectionMap">
        select * from work_collection where collection_id=#{collectionId}
    </select>
    <!--通过groupBy和having筛选查询order_by重复-->
    <select id="selectCollectionOrderBy" resultMap="workCollectionMap">
        select collection_order_by from work_collection group by collection_order_by having count(*)>1
    </select>

    //新增作品集
    int insertCollection(WorkCollection workCollection);

    //保存排序-通过id查询作品集
    WorkCollection selectCollection(WorkCollection workCollection);

    //保存排序-查询order_by字段是否有重复
    List<WorkCollection> selectCollectionOrderBy();

    //保存排序
    int updateOrderBy(List<WorkCollection> list);

 //保存排序-通过id查询作品集
    public WorkCollection selectCollection(WorkCollection workCollection){
        return workCollectionMapper.selectCollection(workCollection);
    }

    //保存排序-查询order_by字段是否有重复
    public List<WorkCollection> selectCollectionOrderBy(){
        return workCollectionMapper.selectCollectionOrderBy();
    }

    //保存排序
    public int updateOrderBy(List<WorkCollection> list){ return workCollectionMapper.updateOrderBy(list);}