商品模块实现

商品模块是商城系统的核心模块，包括商品管理、商品查询、商品搜索等功能。本节将学习如何实现完整的商品模块。

本节将学习：商品列表查询、商品详情查询、商品搜索，以及商品分类。

商品列表查询

分页查询实现

package com.example.ecommerce.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.ecommerce.entity.Product;
import com.example.ecommerce.mapper.ProductMapper;
import com.example.ecommerce.service.ProductService;
import org.springframework.stereotype.Service;

@Service
public class ProductServiceImpl extends ServiceImpl<ProductMapper, Product> implements ProductService {
    
    @Override
    public Page<Product> getProductList(Integer current, Integer size, Long categoryId) {
        Page<Product> page = new Page<>(current, size);
        LambdaQueryWrapper<Product> wrapper = new LambdaQueryWrapper<>();
        
        // 按分类筛选
        if (categoryId != null) {
            wrapper.eq(Product::getCategoryId, categoryId);
        }
        
        // 只查询上架商品
        wrapper.eq(Product::getStatus, 1);
        
        // 按创建时间倒序
        wrapper.orderByDesc(Product::getCreateTime);
        
        return page(page, wrapper);
    }
}

Controller 实现

@RestController
@RequestMapping("/api/products")
public class ProductController {
    
    @Autowired
    private ProductService productService;
    
    @GetMapping
    public Result<Page<Product>> getProductList(
        @RequestParam(defaultValue = "1") Integer current,
        @RequestParam(defaultValue = "10") Integer size,
        @RequestParam(required = false) Long categoryId
    ) {
        Page<Product> page = productService.getProductList(current, size, categoryId);
        return Result.success(page);
    }
}

商品详情查询

详情查询实现

@Override
public Product getProductDetail(Long id) {
    Product product = getById(id);
    if (product == null) {
        throw new BusinessException("Product not found");
    }
    if (product.getStatus() == 0) {
        throw new BusinessException("Product is off-shelf");
    }
    return product;
}

Controller 实现

@GetMapping("/{id}")
public Result<Product> getProductDetail(@PathVariable Long id) {
    Product product = productService.getProductDetail(id);
    return Result.success(product);
}

商品搜索

搜索流程

搜索实现

@Override
public Page<Product> searchProducts(String keyword, Long categoryId, String sortBy, 
                                   Integer current, Integer size) {
    Page<Product> page = new Page<>(current, size);
    LambdaQueryWrapper<Product> wrapper = new LambdaQueryWrapper<>();
    
    // 关键词搜索
    if (keyword != null && !keyword.isEmpty()) {
        wrapper.and(w -> w.like(Product::getName, keyword)
                         .or()
                         .like(Product::getDescription, keyword));
    }
    
    // 分类筛选
    if (categoryId != null) {
        wrapper.eq(Product::getCategoryId, categoryId);
    }
    
    // 只查询上架商品
    wrapper.eq(Product::getStatus, 1);
    
    // 排序
    if ("price_asc".equals(sortBy)) {
        wrapper.orderByAsc(Product::getPrice);
    } else if ("price_desc".equals(sortBy)) {
        wrapper.orderByDesc(Product::getPrice);
    } else {
        wrapper.orderByDesc(Product::getCreateTime);
    }
    
    return page(page, wrapper);
}

Controller 实现

@GetMapping("/search")
public Result<Page<Product>> searchProducts(
    @RequestParam(required = false) String keyword,
    @RequestParam(required = false) Long categoryId,
    @RequestParam(required = false) String sortBy,
    @RequestParam(defaultValue = "1") Integer current,
    @RequestParam(defaultValue = "10") Integer size
) {
    Page<Product> page = productService.searchProducts(keyword, categoryId, sortBy, current, size);
    return Result.success(page);
}

商品分类

分类树结构

分类实体类

package com.example.ecommerce.entity;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;

import java.time.LocalDateTime;
import java.util.List;

@Data
@TableName("category")
public class Category {
    @TableId(type = IdType.AUTO)
    private Long id;
    
    private String name;
    private Long parentId;
    private Integer level;
    private Integer sortOrder;
    private LocalDateTime createTime;
    private LocalDateTime updateTime;
    
    // 子分类（不映射到数据库）
    @TableField(exist = false)
    private List<Category> children;
}

分类查询实现

package com.example.ecommerce.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.ecommerce.entity.Category;
import com.example.ecommerce.mapper.CategoryMapper;
import com.example.ecommerce.service.CategoryService;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.stream.Collectors;

@Service
public class CategoryServiceImpl extends ServiceImpl<CategoryMapper, Category> implements CategoryService {
    
    @Override
    public List<Category> getCategoryTree() {
        // 查询所有分类
        List<Category> allCategories = list();
        
        // 构建分类树
        return allCategories.stream()
            .filter(category -> category.getParentId() == 0)
            .map(category -> {
                category.setChildren(getChildren(category.getId(), allCategories));
                return category;
            })
            .collect(Collectors.toList());
    }
    
    private List<Category> getChildren(Long parentId, List<Category> allCategories) {
        return allCategories.stream()
            .filter(category -> category.getParentId().equals(parentId))
            .map(category -> {
                category.setChildren(getChildren(category.getId(), allCategories));
                return category;
            })
            .collect(Collectors.toList());
    }
}

Controller 实现

@RestController
@RequestMapping("/api/categories")
public class CategoryController {
    
    @Autowired
    private CategoryService categoryService;
    
    @GetMapping("/tree")
    public Result<List<Category>> getCategoryTree() {
        List<Category> tree = categoryService.getCategoryTree();
        return Result.success(tree);
    }
    
    @GetMapping("/{id}/products")
    public Result<Page<Product>> getProductsByCategory(
        @PathVariable Long id,
        @RequestParam(defaultValue = "1") Integer current,
        @RequestParam(defaultValue = "10") Integer size
    ) {
        Page<Product> page = productService.getProductList(current, size, id);
        return Result.success(page);
    }
}

商品管理

商品创建

@Override
@Transactional(rollbackFor = Exception.class)
public Product createProduct(Product product) {
    // 验证分类是否存在
    Category category = categoryService.getById(product.getCategoryId());
    if (category == null) {
        throw new BusinessException("Category not found");
    }
    
    // 设置默认状态
    product.setStatus(1);
    
    // 保存商品
    save(product);
    
    return product;
}

商品更新

@Override
@Transactional(rollbackFor = Exception.class)
public Product updateProduct(Long id, Product product) {
    Product existProduct = getById(id);
    if (existProduct == null) {
        throw new BusinessException("Product not found");
    }
    
    product.setId(id);
    updateById(product);
    
    return product;
}

完整商品模块示例

ProductService 接口

package com.example.ecommerce.service;

import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.IService;
import com.example.ecommerce.entity.Product;

public interface ProductService extends IService<Product> {
    Page<Product> getProductList(Integer current, Integer size, Long categoryId);
    Product getProductDetail(Long id);
    Page<Product> searchProducts(String keyword, Long categoryId, String sortBy, 
                                 Integer current, Integer size);
    Product createProduct(Product product);
    Product updateProduct(Long id, Product product);
}

ProductController 完整示例

package com.example.ecommerce.controller;

import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.ecommerce.common.Result;
import com.example.ecommerce.entity.Product;
import com.example.ecommerce.service.ProductService;
import jakarta.validation.Valid;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/products")
public class ProductController {
    
    @Autowired
    private ProductService productService;
    
    @GetMapping
    public Result<Page<Product>> getProductList(
        @RequestParam(defaultValue = "1") Integer current,
        @RequestParam(defaultValue = "10") Integer size,
        @RequestParam(required = false) Long categoryId
    ) {
        Page<Product> page = productService.getProductList(current, size, categoryId);
        return Result.success(page);
    }
    
    @GetMapping("/{id}")
    public Result<Product> getProductDetail(@PathVariable Long id) {
        Product product = productService.getProductDetail(id);
        return Result.success(product);
    }
    
    @GetMapping("/search")
    public Result<Page<Product>> searchProducts(
        @RequestParam(required = false) String keyword,
        @RequestParam(required = false) Long categoryId,
        @RequestParam(required = false) String sortBy,
        @RequestParam(defaultValue = "1") Integer current,
        @RequestParam(defaultValue = "10") Integer size
    ) {
        Page<Product> page = productService.searchProducts(keyword, categoryId, sortBy, current, size);
        return Result.success(page);
    }
    
    @PostMapping
    public Result<Product> createProduct(@RequestBody @Valid Product product) {
        Product created = productService.createProduct(product);
        return Result.success("Product created successfully", created);
    }
    
    @PutMapping("/{id}")
    public Result<Product> updateProduct(@PathVariable Long id, 
                                        @RequestBody @Valid Product product) {
        Product updated = productService.updateProduct(id, product);
        return Result.success("Product updated successfully", updated);
    }
}

官方资源

• MyBatis-Plus 条件构造器：https://baomidou.com/pages/10c804/
• MyBatis-Plus 分页插件：https://baomidou.com/pages/97710a/

本节小结

在本节中，我们实现了：

第一个是商品列表查询。 支持分页查询和分类筛选。

第二个是商品详情查询。 根据 ID 查询商品详情。

第三个是商品搜索。 支持关键词搜索、分类筛选和价格排序。

第四个是商品分类。 实现分类树结构查询。

这就是商品模块实现。商品模块提供了完整的商品管理功能，是商城系统的核心。

在下一节，我们将学习如何实现订单模块，包括订单创建、订单查询等功能。