电商系统：分类模块
一、功能描述
查找多级目录，返回结果如下
二、查询目录
1、先查询出一级目录，再递归查询多级目录
2、根据sortorder对目录进行排序
@Service
public class CategoryServiceImpl implements ICategoryService {
@Autowired
CategoryMapper categoryMapper;
@Override
public ResponseVO<List<CategoryVO>> selectAll() {
List<CategoryVO> categoryVOList = new ArrayList<>();
List<Category> categories = categoryMapper.selectAll();
for(Category category : categories){
if(category.getParentId().equals(ROOT_PARENT_ID)){
CategoryVO categoryVO = new CategoryVO();
BeanUtils.copyProperties(category, categoryVO);
categoryVOList.add(categoryVO);
}
}
categoryVOList.sort(Comparator.comparing(CategoryVO::getSortOrder).reversed());
//查询子目录
findSubCategory(categoryVOList, categories);
return ResponseVO.success(categoryVOList);
}
private void findSubCategory(List<CategoryVO> categoryVOList, List<Category> categories){
for(CategoryVO categoryVO : categoryVOList){
List<CategoryVO> subCategoryVOList = new ArrayList<>();
for(Category category : categories){
//如果查到，设置subCategory，继续往下查
if(category.getParentId().equals(categoryVO.getId())){
CategoryVO categoryVO1 = new CategoryVO();
BeanUtils.copyProperties(category, categoryVO1);
subCategoryVOList.add(categoryVO1);
}
subCategoryVOList.sort(Comparator.comparing(CategoryVO::getSortOrder).reversed());
findSubCategory(subCategoryVOList, categories);
}
categoryVO.setSubCategories(subCategoryVOList);
}
}
}