电商生鲜网站开发（四）——后台开发：商品模块-图片上传/多条件拼接sql

增加商品

上传图片

更新商品

删除商品

批量上下架

文件名UUID

通用唯一识别码（Universally Unique Identifier）

防止重名、防止发图

生成规则：日期和时间、MAC地址、HashCode、随机数

配置application.properties

# 上传文件的路径，根据部署情况自行修改 该值注入到Constan类中
file.upload.dir=/Users/cat/documents/project/java/online_mall/mall-prepare-static

Constant常量类

package com.learn2333.mall.common;

import com.google.common.collect.Sets;
import com.learn2333.mall.exception.MallException;
import com.learn2333.mall.exception.MallExceptionEnum;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.util.Set;


@Component
public class Constant {
    public static final String MALL_USER = "mall_user";
    public static final String SALT = "learn2333";

    public static String FILE_UPLOAD_DIR;

  //因为是static无法直接注入，使用set方法为静态变量注入赋值
    @Value("${file.upload.dir}")
    public void setFileUploadDir(String fileUploadDir) {
        FILE_UPLOAD_DIR = fileUploadDir;
    }

controller

    @PostMapping("/admin/upload/file")
    public ApiRestResponse upload(HttpServletRequest httpServletRequest,
                                  @RequestParam("file") MultipartFile file) {
        String fileName = file.getOriginalFilename();
        String suffixName = fileName.substring(fileName.lastIndexOf("."));  //后缀
        //生成文件名称UUID
        UUID uuid = UUID.randomUUID();
        String newFileName = uuid.toString() + suffixName;
        //创建文件
        File fileDirectory = new File(Constant.FILE_UPLOAD_DIR);
        File destFile = new File(Constant.FILE_UPLOAD_DIR + newFileName);
        //如果文件夹不存在
        if (!fileDirectory.exists()) {
            if (!fileDirectory.mkdir()) {//创建文件夹
                throw new MallException(MallExceptionEnum.MKDIR_FAILED);
            }
        }
        //文件写入
        try {
            file.transferTo(destFile);
        } catch (IOException e) {
            e.printStackTrace();
        }
        //返回文件地址
        try {
            return ApiRestResponse
                    .success(getHost(new URI(httpServletRequest.getRequestURL() + "")) + "/images/"
                            + newFileName);
        } catch (URISyntaxException e) {
            return ApiRestResponse.error(MallExceptionEnum.UPLOAD_FAILED);
        }
    }

    
    private URI getHost(URI uri) {
        URI effectiveURI;
        try {
            effectiveURI = new URI(uri.getScheme(), uri.getUserInfo(), uri.getHost(), uri.getPort(),
                    null, null, null);
        } catch (URISyntaxException e) {
            effectiveURI = null;
        }
        return effectiveURI;
    }

上传图片后回显

配置SpringBootWebMvcConfig

静态资源到本地目录到映射

package com.learn2333.mall.config;

import com.learn2333.mall.common.Constant;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;


@Configuration
public class MallWebMvcConfig implements WebMvcConfigurer {

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
      //图片目录映射
        registry.addResourceHandler("/images
public class ProductListQuery {

    private String keyword;
  //查询一个目录下的商品，不一定是只有当前目录下，还包含子目录，子子目录下的商品；因此之前传入一个目录的id现在还要获取它子目录的所有id
    private List categoryIds;

get;set;
}

productServiceImpl

    @Override
    public PageInfo list(ProductListReq productListReq) {
        //构建Query对象
        ProductListQuery productListQuery = new ProductListQuery();

        //搜索处理
        if (!StringUtils.isEmpty(productListReq.getKeyword())) {
            String keyword = new StringBuilder().append("%").append(productListReq.getKeyword())
                    .append("%").toString();
            productListQuery.setKeyword(keyword);
        }

        //目录处理：如果查某个目录下的商品，不仅是需要查出该目录下的，还要把所有子目录的所有商品都查出来，所以要拿到一个目录id的List
        if (productListReq.getCategoryId() != null) {
            //复用之前写过的传入目录id查询子目录方法listCategoryForCustomer
            List categoryVOList = categoryService.listCategoryForCustomer(productListReq.getCategoryId());
            //将得到的树形目录结构categoryVOList展开
            ArrayList categoryIds = new ArrayList<>();
            categoryIds.add(productListReq.getCategoryId());
            //用下面定义的方法来处理子目录的遍历，
            //通过下面的函数处理就可以将categoryVOList中子目录所有id放入categoryIds，因为传入的是List引用类型
            getCategoryIds(categoryVOList, categoryIds);
            productListQuery.setCategoryIds(categoryIds);
        }

        //排序处理
        String orderBy = productListReq.getOrderBy(); //为了系统安全，不能传入什么就直接按照什么排序，而是要拿到前台传入的排序规则
        if (Constant.ProductListOrderBy.PRICE_ASC_DESC.contains(orderBy)) {	//contains判断是否包含
            PageHelper.startPage(productListReq.getPageNum(), productListReq.getPageSize(), orderBy);
        } else {
            PageHelper.startPage(productListReq.getPageNum(), productListReq.getPageSize());
        }

        List productList = productMapper.selectList(productListQuery);
        PageInfo pageInfo = new PageInfo(productList);
        return pageInfo;
    }

    //递归遍历子目录
    private void getCategoryIds(List categoryVOList, ArrayList categoryIds) {
        for (int i = 0; i < categoryVOList.size(); i++) {
            CategoryVO categoryVO = categoryVOList.get(i);
            if (categoryVO != null) {
                categoryIds.add(categoryVO.getId());
                getCategoryIds(categoryVO.getChildCategory(), categoryIds);
            }
        }
    }

常量(排序方式接口)

package com.learn2333.mall.common;

import com.google.common.collect.Sets;
import com.learn2333.mall.exception.MallException;
import com.learn2333.mall.exception.MallExceptionEnum;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.util.Set;


@Component
public class Constant {
    public static final String MALL_USER = "mall_user";
    public static final String SALT = "learn2333";

    public static String FILE_UPLOAD_DIR;

    @Value("${file.upload.dir}")
    public void setFileUploadDir(String fileUploadDir) {
        FILE_UPLOAD_DIR = fileUploadDir;
    }

    public interface ProductListOrderBy {
        Set PRICE_ASC_DESC = Sets.newHashSet("price desc", "price asc");

    }

ProductMapper接口

    List selectList(@Param("query") ProductListQuery query);

ProductMapper

    
        select
        
        from mall_product
        
            
                and name like #{query.keyword}
            
            
                and category_id in
                
                    #{item}
                
            
          
            and status = 1
        
        order by update_time desc
    

排序功能、MyBatis PageHelper、枚举：order by

商品的搜索、排序、目录查询

常见问题：更新和新增不要用一个接口，虽然方便，但是从长期维护角度每一个接口要明确分工；排序的时候要用常量枚举判断，不要直接传入，否则可能被黑客利用，攻击数据库。