数据结构设计

API：

{
    "code": 0,
    "msg": "成功",
    "data": [
        {
            "name": "热榜",
            "type": 1,
            "foods": [
                {
                    "id": "123456",
                    "name": "皮蛋粥",
                    "price": 1.2,
                    "description": "好吃的皮蛋粥",
                    "icon": "http://xxx.com",
                }
            ]
        },
        {
            "name": "好吃的",
            "type": 2,
            "foods": [
                {
                    "id": "123457",
                    "name": "慕斯蛋糕",
                    "price": 10.9,
                    "description": "美味爽口",
                    "icon": "http://xxx.com",
                }
            ]
        }
    ]
}

　　controller：

@GetMapping("/list")
    public ResultVO<ProductVO> list() {
        //1. 查询所有在架的商品
        List<ProductInfo> productInfoList = productService.findUpAll();

        //2. 获取类目type列表
        List<Integer> categoryTypeList = productInfoList.stream()
                .map(ProductInfo::getCategoryType)
                .collect(Collectors.toList());

        //3. 从数据库查询类目
        List<ProductCategory> categoryList = categoryService.findByCategoryTypeIn(categoryTypeList);

        //4. 构造数据
        List<ProductVO> productVOList = new ArrayList<>();
        for (ProductCategory productCategory: categoryList) {
            ProductVO productVO = new ProductVO();
            productVO.setCategoryName(productCategory.getCategoryName());
            productVO.setCategoryType(productCategory.getCategoryType());

            List<ProductInfoVO> productInfoVOList = new ArrayList<>();
            for (ProductInfo productInfo: productInfoList) {
                if (productInfo.getCategoryType().equals(productCategory.getCategoryType())) {
                    ProductInfoVO productInfoVO = new ProductInfoVO();
                    BeanUtils.copyProperties(productInfo, productInfoVO);
                    productInfoVOList.add(productInfoVO);
                }
            }
            productVO.setProductInfoVOList(productInfoVOList);
            productVOList.add(productVO);
        }

        return ResultVOUtil.success(productVOList);
    }

　　dataobject： 

ProductCategory

package com.imooc.product.dataobject;

import lombok.Data;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import java.util.Date;

@Data
@Entity
public class ProductCategory {

    @Id
    @GeneratedValue
    private Integer categoryId;

    /** 类目名字. */
    private String categoryName;

    /** 类目编号. */
    private Integer categoryType;

    private Date createTime;

    private Date updateTime;
}

　　

ProductInfo

package com.imooc.product.dataobject;

import lombok.Data;

import javax.persistence.Entity;
import javax.persistence.Id;
import java.math.BigDecimal;
import java.util.Date;

/**
 * Created by 廖师兄
 * 2017-12-09 21:23
 */
@Data  //自动生成set、get方法
//@Table(name = "T_proxxx")
@Entity //生成数据库表
public class ProductInfo {

    @Id
    private String productId;

    /** 名字. */
    private String productName;

    /** 单价. */
    private BigDecimal productPrice;

    /** 库存. */
    private Integer productStock;

    /** 描述. */
    private String productDescription;

    /** 小图. */
    private String productIcon;

    /** 状态, 0正常1下架. */
    private Integer productStatus;

    /** 类目编号. */
    private Integer categoryType;

    private Date createTime;

    private Date updateTime;
}

　　

　　VO:

ProductInfoVO

package com.imooc.product.VO;

import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;

import java.math.BigDecimal;

/**
 * Created by xyyou
 * 2019/10/11 22:40
 */
@Data
public class ProductInfoVO {

    @JsonProperty("id")
    private String productId;

    @JsonProperty("name")
    private String productName;

    @JsonProperty("price")
    private BigDecimal productPrice;

    @JsonProperty("description")
    private String productDescription;

    @JsonProperty("icon")
    private String productIcon;
}

　　ProductVO

package com.imooc.product.VO;

import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;

import java.util.List;

/**
 * Created by xyyou
 * 2019/10/11 22:37
 */
@Data
public class ProductVO {

    @JsonProperty("name")
    private String categoryName;

    @JsonProperty("type")
    private Integer categoryType;

    @JsonProperty("foods")
    List<ProductInfoVO> productInfoVOList;
}

　　ResultVO

package com.imooc.product.VO;

import lombok.Data;

/**
 * http返回的最外层对象
 * Created by xyyou
 * 2019/10/11 22:34
 */
@Data
public class ResultVO<T> {

    /**
     * 错误码
     */
    private Integer code;

    /**
     * 提示信息
     */
    private String msg;

    /**
     * 具体内容
     */
    private T data;

}