查询商品分类下的所有商品（分类级别不限）

1. 查询所有商品分类
2. 遍历每个分类
3. 如果能查到父级，就将子类放入父级中
4. 根据分类Id查询商品列表
5. 最后将查询到的商品放入分类中

controller代码

@GetMapping("/list")
    @ApiOperation(value = "分类下的商品", notes = "所有分类包含商品", produces = "application/json")
    public ResultPoJo<List<YxJpProductCategory>> getCategoryproducts(Pagination pagination,String keyword) {
        LambdaQueryWrapper<YxJpProductCategory> queryWrapper = new LambdaQueryWrapper<YxJpProductCategory>().orderByAsc(YxJpProductCategory::getSort).orderByDesc(YxJpProductCategory::getCreateDate);
        CommonUtil.emptyStr(keyword).ifPresent(key -> queryWrapper.and(andQw ->
                andQw.or(orQw -> orQw.like(YxJpProductCategory::getName, key))

        ));
        // 查询所有分类
        List<YxJpProductCategory> categoryList = categoryService.list(queryWrapper);//查询所有分类
        List<YxJpProductCategory> rsList = categoryList;
        if (StrUtil.isBlank(keyword)) {//关键字为空（用于搜索）
            categoryList.forEach(category -> {//遍历每个分类
                if (!"0".equals(category.getParentId())) {//父id不等于0 （0为顶级分类）
                    //查找父级分类（包含子类）
                    categoryList.stream().filter(ca -> ca.getId().equals(category.getParentId())).findFirst()
                            .ifPresent(parentCategory -> {//如果存在父子关系
                                List<YxJpProductCategory> children = parentCategory.getChildren();
                                if (ObjectUtil.isNull(children)) {
                                    children = Lists.newArrayList();
                                }
                                //根据商品分类查询商品
                                IPage<ProductDetilVo> page =  productService.getJpProductByCategory(pagination.page(),keyword,category.getId());
                                category.setProducts(page);
                                //将子级放到父级的children中
                                children.add(category);
                                parentCategory.setChildren(children);
                            });
                }
            });
            rsList = categoryList.stream().filter(category -> "0".equals(category.getParentId())).collect(Collectors.toList());
        }
        return ResultPoJo.ok(rsList);
    }

• 在实体类中需要加入children的列表（类型是自己本身）
• 需要加入商品列表的属性

实体类代码

public class YxJpProductCategory extends BaseEntity<YxJpProductCategory> {

private static final long serialVersionUID=1L;

    private String id;

    @ApiModelProperty(value = "上级分类的编号：0表示一级分类")
    private String parentId;

    @ApiModelProperty(value = "所有父级编号")
    private String parentIds;

    @ApiModelProperty(value = "分类名称")
    private String name;

    @ApiModelProperty(value = "分类级别：0->1级；1->2级")
    private String level;

    @ApiModelProperty(value = "产品数量")
    private Integer productCount;

    @ApiModelProperty(value = "排序")
    private Integer sort;

    @ApiModelProperty(value = "图标")
    private String icon;

    @ApiModelProperty(value = "关键词")
    private String keywords;

    @ApiModelProperty(value = "描述")
    private String description;

    @ApiModelProperty(value = "创建者",hidden = true)
    private String createBy;

    @ApiModelProperty(value = "创建时间",example = "2020-05-19 00:00:00",hidden = true)
    private Date createDate;

    @ApiModelProperty(value = "更新者",hidden = true)
    private String updateBy;

    @ApiModelProperty(value = "更新时间",example = "2020-05-19 00:00:00",hidden = true)
    private Date updateDate;

    private String remarks;

    @TableLogic
    @ApiModelProperty(value = "删除标记",example = "0",hidden = true)
    private String delFlag;

    private String openid;


    @TableField(select = false,exist = false)
    @ApiModelProperty(hidden = true)
    private List<YxJpProductCategory> children;

    @TableField(select = false,exist = false)
    @ApiModelProperty(hidden = true)
    private IPage<ProductDetilVo> products;

    @Override
    protected Serializable pkVal() {
        return this.id;
    }

}