tkMapper单表查询_实际应用

package com.qfedu.fmmall.service.impl;

import com.qfedu.fmmall.dao.ProductImgMapper;
import com.qfedu.fmmall.dao.ProductMapper;
import com.qfedu.fmmall.dao.ProductSkuMapper;
import com.qfedu.fmmall.entity.Product;
import com.qfedu.fmmall.entity.ProductImg;
import com.qfedu.fmmall.entity.ProductSku;
import com.qfedu.fmmall.entity.ProductVO;
import com.qfedu.fmmall.service.ProductService;
import com.qfedu.fmmall.vo.ResStatus;
import com.qfedu.fmmall.vo.ResultVO;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import tk.mybatis.mapper.entity.Example;

import java.util.HashMap;
import java.util.List;

/**
 * @author beyondx
 * @date Created in 2022/08/16/ 11:00
 */
@Service
public class ProductServiceImpl implements ProductService {
    @Autowired
    private ProductMapper productMapper;
    @Autowired
    private ProductImgMapper productImgMapper;
    @Autowired
    private ProductSkuMapper productSkuMapper;

    @Override
    public ResultVO listRecommendProducts() {
        List<ProductVO> productVOS = productMapper.selectRecommendProducts();
        ResultVO resultVO = new ResultVO(ResStatus.OK, "success", productVOS);
        return resultVO;
    }

    @Transactional(propagation = Propagation.SUPPORTS) // 事务的隔离级别
    @Override
    public ResultVO getProductBasicInfo(String productId) {
        // 1.商品基本信息
        Example example = new Example(Product.class);
        Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("productId", productId);
        criteria.andEqualTo("productStatus", 1); // 状态为1表示 上架商品; 上午商品推荐的时候, 就需要有这个

        List<Product> products = productMapper.selectByExample(example);
        if(products.size() > 0) {
            // 只有 有了 商品基本信息, 才有必要查询 里面的; 这里相当于 容错
            // size() > 0商品存在; 才有必要查 商品图片, 商品套餐
            // 2.商品图片
            Example example1 = new Example(ProductImg.class);
            Example.Criteria criteria1 = example.createCriteria();
            criteria1.andEqualTo("itemId", productId);
            List<ProductImg> productImgs = productImgMapper.selectByExample(example);
            // 3.商品套餐
            Example example2 = new Example(ProductSku.class);
            Example.Criteria criteria2 = example2.createCriteria();
            criteria2.andEqualTo("productId", productId);
            criteria2.andEqualTo("status", 1);
            List<ProductSku> productSkus = productSkuMapper.selectByExample(example2);

            HashMap<String, Object> basicInfo = new HashMap<>();
            basicInfo.put("product", products.get(0));
            basicInfo.put("productImgs", productImgs);
            basicInfo.put("productSkus", productSkus);
            return new ResultVO(ResStatus.OK, "success", basicInfo);
        } else {
            // 商品不存在
            return new ResultVO(ResStatus.NO, "查询的商品不存在!", null);
        }
    }
}
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挖坑
了解一下 tkMapper, 在实际项目中, 使用普遍吗