fix:更新校验逻辑，优化代码

ruoyi-modules/ruoyi-commodityManagement/src/main/java/org/dromara/commodityManagement/service/impl/BrandServiceImpl.java

@@ -15,37 +15,55 @@ import org.dromara.common.mybatis.core.page.PageQuery;
 import org.dromara.common.mybatis.core.page.TableDataInfo;
 import org.springframework.stereotype.Service;
 
-@RequiredArgsConstructor
+/**
+ * 品牌服务实现
+ */
 @Service
+@RequiredArgsConstructor
 public class BrandServiceImpl implements BrandService {
 
     private final BrandMapper brandMapper;
 
     /**
-     * 查询品牌列表
-     * @param brand 品牌Bo对象
+     * 品牌类型
+     */
+    private static final String BRAND_TYPE = "2";
+
+    /**
+     * 根据Brand对象分页查询品牌数据
+     * @param brandBo BrandBo对象
      * @param pageQuery 查询条件
      * @return 分页结果
      */
     @Override
-    public TableDataInfo<BrandVo> selectPageBrandList(BrandBo brand,PageQuery pageQuery) {
+    public TableDataInfo<BrandVo> selectPageBrandList(BrandBo brandBo,PageQuery pageQuery) {
         QueryWrapper<Brand> qw = new QueryWrapper<>();
-        qw.eq(StringUtils.isNotBlank(brand.getName()), "name", brand.getName());
-        qw.eq("type", "2");
+        qw.eq(StringUtils.isNotBlank(brandBo.getName()), "name", brandBo.getName());
+        qw.eq("type", BRAND_TYPE);
         Page<BrandVo> page = brandMapper.selectVoPage(pageQuery.build(), qw);
         return TableDataInfo.build(page);
     }
 
+    /**
+     * 新增品牌
+     * @param brandBo BrandBo对象
+     * @return 结果
+     */
     @Override
     public int insertBrand(BrandBo brandBo) {
-        Brand brand = MapstructUtils.convert(brandBo, Brand.class);
-        if (null != brandMapper.selectVoById(brand.getId())){
+        if (null != brandMapper.selectVoById(brandBo.getId())){
             throw new ServiceException("品牌已存在！");
         }
+        Brand brand = MapstructUtils.convert(brandBo, Brand.class);
         validEntityBeforeSave(brand);
         return brandMapper.insert(brand);
     }
 
+    /**
+     * 修改品牌
+     * @param brandBo BrandBo对象
+     * @return 结果
+     */
     @Override
     public int updateBrand(BrandBo brandBo) {
         Brand brand = MapstructUtils.convert(brandBo, Brand.class);
@@ -55,6 +73,11 @@ public class BrandServiceImpl implements BrandService {
         return brandMapper.update(brand,qw);
     }
 
+    /**
+     * 删除品牌
+     * @param brandId BrandId
+     * @return 结果
+     */
     @Override
     public int deleteBrandById(int brandId) {
         return brandMapper.deleteById(brandId);