package com.how2java.tmall.pojo;

import java.util.List;

public class Category {
    private Integer id;

    private String name;

    /*如下是非数据库字段*/
    private List<Product> products;

    private List<List<Product>> productsByRow;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name == null ? null : name.trim();
    }

    public List<Product> getProducts() {
        return products;
    }

    public void setProducts(List<Product> products) {
        this.products = products;
    }

    public List<List<Product>> getProductsByRow() {
        return productsByRow;
    }

    public void setProductsByRow(List<List<Product>> productsByRow) {
        this.productsByRow = productsByRow;
    }
}

package com.how2java.tmall.service;
 
import java.util.List;

import com.how2java.tmall.pojo.Category;
import com.how2java.tmall.pojo.Product;

public interface ProductService {
    void add(Product p);
    void delete(int id);
    void update(Product p);
    Product get(int id);
    List list(int cid);
    void setFirstProductImage(Product p);

    void fill(List<Category> cs);

    void fill(Category c);

    void fillByRow(List<Category> cs);
}

package com.how2java.tmall.service.impl;

import com.how2java.tmall.mapper.ProductMapper;
import com.how2java.tmall.pojo.Category;
import com.how2java.tmall.pojo.Product;
import com.how2java.tmall.pojo.ProductExample;
import com.how2java.tmall.pojo.ProductImage;
import com.how2java.tmall.service.CategoryService;
import com.how2java.tmall.service.ProductImageService;
import com.how2java.tmall.service.ProductService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;
@Service
public class ProductServiceImpl implements ProductService {
    @Autowired
    ProductMapper productMapper;
    @Autowired
    CategoryService categoryService;
    @Autowired
    ProductImageService productImageService;

    @Override
    public void add(Product p) {
        productMapper.insert(p);
    }

    @Override
    public void delete(int id) {
        productMapper.deleteByPrimaryKey(id);
    }

    @Override
    public void update(Product p) {
        productMapper.updateByPrimaryKeySelective(p);
    }

    @Override
    public Product get(int id) {
        Product p = productMapper.selectByPrimaryKey(id);
        setFirstProductImage(p);
        setCategory(p);
        return p;
    }

    public void setCategory(List<Product> ps){
        for (Product p : ps)
            setCategory(p);
    }
    public void setCategory(Product p){
        int cid = p.getCid();
        Category c = categoryService.get(cid);
        p.setCategory(c);
    }

    @Override
    public List list(int cid) {
        ProductExample example = new ProductExample();
        example.createCriteria().andCidEqualTo(cid);
        example.setOrderByClause("id desc");
        List result = productMapper.selectByExample(example);
        setCategory(result);
        setFirstProductImage(result);
        return result;
    }

    @Override
    public void setFirstProductImage(Product p) {
        List<ProductImage> pis = productImageService.list(p.getId(), ProductImageService.type_single);
        if (!pis.isEmpty()) {
            ProductImage pi = pis.get(0);
            p.setFirstProductImage(pi);
        }
    }

    @Override
    public void fill(List<Category> cs) {
        for (Category c : cs) {
            fill(c);
        }
    }

    @Override
    public void fill(Category c) {
        List<Product> ps = list(c.getId());
        c.setProducts(ps);
    }

    @Override
    public void fillByRow(List<Category> cs) {
        int productNumberEachRow = 8;
        for (Category c : cs) {
            List<Product> products =  c.getProducts();
            List<List<Product>> productsByRow =  new ArrayList<>();
            for (int i = 0; i < products.size(); i+=productNumberEachRow) {
                int size = i+productNumberEachRow;
                size= size>products.size()?products.size():size;
                List<Product> productsOfEachRow =products.subList(i, size);
                productsByRow.add(productsOfEachRow);
            }
            c.setProductsByRow(productsByRow);
        }
    }

    public void setFirstProductImage(List<Product> ps) {
        for (Product p : ps) {
            setFirstProductImage(p);
        }
    }

}

package com.how2java.tmall.controller;

import com.how2java.tmall.pojo.Category;
import com.how2java.tmall.service.*;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.List;

@Controller
@RequestMapping("")
public class ForeController {
    @Autowired
    CategoryService categoryService;
    @Autowired
    ProductService productService;
    @Autowired
    UserService userService;
    @Autowired
    ProductImageService productImageService;
    @Autowired
    PropertyValueService propertyValueService;
    @Autowired
    OrderService orderService;
    @Autowired
    OrderItemService orderItemService;

    @RequestMapping("forehome")
    public String home(Model model) {
        List<Category> cs= categoryService.list();
        productService.fill(cs);
        productService.fillByRow(cs);
         model.addAttribute("cs", cs);
        return "fore/home";
    }

}