引言

返回树结构菜单列表：https://blog.csdn.net/z929118967/article/details/128025800

I 排序

需求：

思路：交换排序字段

1.1 Dto

    @ApiModelProperty(value = "排序")@TableField("sort_num")private Integer sortNum;

1.2 新增节点的默认排序

/*用于新增时的排序字段*/private void setSortNum4create(TSysMenu menu){LambdaQueryWrapper<TSysMenu> queryWrapper = new LambdaQueryWrapper<>();if(menu.getParentId() == null){queryWrapper.isNull(TSysMenu::getParentId);}else{queryWrapper.eq(null != menu.getParentId(),TSysMenu::getParentId,menu.getParentId());}queryWrapper.orderByDesc(TSysMenu::getSortNum);var sortCate = tSysMenuMapper.selectOne(queryWrapper.last("limit 1"));if (sortCate!=null){menu.setSortNum(sortCate.getSortNum()+1);}else{menu.setSortNum(0);}}

1.3 对分类进行上移和下移排序

查询最近的兄弟节点进行交换

/*对分类进行排序*/public TSysCollegeCategory sortCategory(Long id,Integer type) throws Exception {if(id ==null){throw CommonException.create(ServerResponse.createByError("id不存在"));}var current = tSysCollegeCategoryMapper.selectById(id);if(current ==null){throw CommonException.create(ServerResponse.createByError("分类不存在"));}LambdaQueryWrapper<TSysCollegeCategory> queryWrapper = new LambdaQueryWrapper<>();// 检查ParentId为空的情况。if(current.getParentId() == null){queryWrapper.isNull(TSysCollegeCategory::getParentId);}else{queryWrapper.eq(null != current.getParentId(),TSysCollegeCategory::getParentId,current.getParentId());}if(type ==1){//上移queryWrapper.lt(TSysCollegeCategory::getSortNum,current.getSortNum()).orderByDesc(TSysCollegeCategory::getSortNum).last("limit 1");}else if(type ==2){//下移queryWrapper.gt(TSysCollegeCategory::getSortNum,current.getSortNum()).orderByAsc(TSysCollegeCategory::getSortNum).last("limit 1");}else{throw CommonException.create(ServerResponse.createByError("type类型错误"));}var next = tSyCollegeCategoryMapper.selectOne(queryWrapper);if(next !=null){var sort = current.getSortNum();current.setSortNum(next.getSortNum());next.setSortNum(sort);tSysCollegeCategoryMapper.updateById(current);tSysCollegeCategoryMapper.updateById(next);}return current;}

1.4 上移和下移排序对应的测试SQL

上移时，获取最近一个的排序字段

select  * from t_organizations where sort_num<4 order by sort_num Desc;

下移时，获取最近的一个记录的排序字段

select  * from t_organizations where sort_num>4 order by sort_num asc;