JavaWeb - 查询任意节点的所有子节点（包括孙子节点）

/*** 递归查询本节点的id及孩子节点的id* @param categoryId* @return*/publicServerResponse<List<Integer>>selectCategoryAndChildrenById(IntegercategoryId){
Set<Category>categorySet=Sets.newHashSet();
findChildCategory(categorySet,categoryId);
List<Integer>categoryIdList=Lists.newArrayList();
if(categoryId!=null){
for(CategorycategoryItem : categorySet){
categoryIdList.add(categoryItem.getId());
        }
    }
returnServerResponse.createBySuccess(categoryIdList);
}
//递归算法,算出子节点privateSet<Category>findChildCategory(Set<Category>categorySet ,IntegercategoryId){
Categorycategory=categoryMapper.selectByPrimaryKey(categoryId);
if(category!=null){
categorySet.add(category);
    }
//查找子节点,递归算法一定要有一个退出的条件List<Category>categoryList=categoryMapper.selectCategoryChildrenByParentId(categoryId);
for(CategorycategoryItem : categoryList){
findChildCategory(categorySet,categoryItem.getId());
    }
returncategorySet;
}