SSM框架学习日记（4）——分类模块

分类管理

管理员可以增加，修改分类，在backend下新建CategoryManageController

项目结构

RequestMapping注解声明url路径，分别新建添加分类方法，更新分类名方法，查询子分类，根据categoryId递归查询方法，自动注入IUserService对象和ICategoryService对象

@Controller
@RequestMapping("/manage/category")
public class CategoryManageController {
....
}

---

添加分类

UserService里要新增一个检验是否是管理员的方法

public ServerResponse checkAdminRole(User user){
        if(user!=null && user.getRole()==Const.Role.ROLE_ADMIN){
            return ServerResponse.createBySuccess();
        }else {
            return ServerResponse.createByError();
        }
    }

判断完身份后执行service里增加分类的方法，

public ServerResponse addCategory(String categoryName,Integer parentId){
        if(parentId == null || StringUtils.isBlank(categoryName)){
            return ServerResponse.createByErrorMessage("添加品类参数错误");
        }

        Category category = new Category();
        category.setName(categoryName);
        category.setParentId(parentId);
        category.setStatus(true);//这个分类是可用的

        int rowCount = categoryMapper.insert(category);
        if(rowCount > 0){
            return ServerResponse.createBySuccess("添加品类成功");
        }
        return ServerResponse.createByErrorMessage("添加品类失败");
    }

controller代码

    @RequestMapping("add_category.do")
    @ResponseBody
    public ServerResponse addCategory(
              HttpSession session, String categoryName, @RequestParam(value = "parentId",defaultValue = "0") int parentId){
        User user = (User)session.getAttribute(Const.CURRENT_USER);
        if(user == null){
            return ServerResponse.createByErrorCodeMessage(ResponseCode.NEED_LOGIN.getCode(),"用户未登录,请登录");
        }
        //校验一下是否是管理员
        if(iUserService.checkAdminRole(user).isSuccess()){
            //是管理员
            //增加我们处理分类的逻辑
            return iCategoryService.addCategory(categoryName,parentId);

        }else{
            return ServerResponse.createByErrorMessage("无权限操作,需要管理员权限");
        }
    }

---

更新分类

方法类似，详见代码

---

查询子分类

在dao层新增一个根据父分类id查询该分类下子分类的方法返回一个List，在CategoryMapper.xml里写sql实现

<select id="selectCategoryChildrenByParentId" resultMap="BaseResultMap" parameterType="int">
    select
    <include refid="Base_Column_List"/>
    from mmall_category
    where parent_id=#{parentId}
 </select>

service调用方法查询之后直接返回给controller

public ServerResponse<List<Category>> getChildrenParallelCategory(Integer categoryId){
        List<Category> categoryList = categoryMapper.selectCategoryChildrenByParentId(categoryId);
        if(CollectionUtils.isEmpty(categoryList)){
            logger.info("未找到当前分类的子分类");
        }
        return ServerResponse.createBySuccess(categoryList);
    }

    @RequestMapping("get_category.do")
    @ResponseBody
    public ServerResponse getChildrenParallelCategory(
              HttpSession session,@RequestParam(value = "categoryId" ,defaultValue = "0") Integer categoryId){
        User user = (User)session.getAttribute(Const.CURRENT_USER);
        if(user == null){
            return ServerResponse.createByErrorCodeMessage(
                      ResponseCode.NEED_LOGIN.getCode(),"用户未登录,请登录");
        }
        if(iUserService.checkAdminRole(user).isSuccess()){
            //查询子节点的category信息,并且不递归,保持平级
            return iCategoryService.getChildrenParallelCategory(categoryId);
        }else{
            return ServerResponse.createByErrorMessage("无权限操作,需要管理员权限");
        }
    }

递归查询分类

service里写一个递归查询，子分类为空时退出

//递归算法,算出子节点
    private Set<Category> findChildCategory(Set<Category> categorySet , Integer categoryId){
        Category category = 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(Category categoryItem : categoryList){
            findChildCategory(categorySet,categoryItem.getId());
        }
        return categorySet;
    }

得到所有的分类信息，调用上面的方法把查到的分类传给controller

public ServerResponse<List<Integer>> selectCategoryAndChildrenById(Integer categoryId){
        Set<Category> categorySet = Sets.newHashSet();
        findChildCategory(categorySet,categoryId);

        List<Integer> categoryIdList = Lists.newArrayList();
        if(categoryId != null){
            for(Category categoryItem : categorySet){
                categoryIdList.add(categoryItem.getId());
            }
        }
        return ServerResponse.createBySuccess(categoryIdList);
    }

其中，Sets和Lists是Guava提供的工具包，提供了一些方便的功能例如集合的互斥、 交集、 并集等

    ....
    @RequestMapping("get_deep_category.do")
    @ResponseBody
    public ServerResponse getCategoryAndDeepChildrenCategory(
               HttpSession session,@RequestParam(value = "categoryId" ,defaultValue = "0") Integer categoryId){
        User user = (User)session.getAttribute(Const.CURRENT_USER);
        if(user == null){
            return ServerResponse.createByErrorCodeMessage(ResponseCode.NEED_LOGIN.getCode(),"用户未登录,请登录");
        }
        if(iUserService.checkAdminRole(user).isSuccess()){
            //查询当前节点的id和递归子节点的id
//            0->10000->100000
            return iCategoryService.selectCategoryAndChildrenById(categoryId);

        }else{
            return ServerResponse.createByErrorMessage("无权限操作,需要管理员权限");
        }
    }