feat(service): 新增分类相关接口并实现功能

- 新增 CategoryService 接口，定义了分类相关操作
- 实现 CategoryServiceImpl 类，完成分类树构建、分类列表获取、分类增删改等功能
- 新增多个分类相关的 DTO 类，用于分类操作的数据传输- 更新 CategoryMapper 接口，调整了部分方法签名

src/main/java/com/example/copykamanotes/mapper/CategoryMapper.java

@@ -12,13 +12,13 @@ public interface CategoryMapper {
 
     int insertBatch(@Param("entities") List<Category> entities);
 
-    List<Category> categoryList(@Param("entities") List<Category> entities);
+    List<Category> categoryList();
 
     Category findById(@Param("id") Integer id);
 
     Category findByIdBatch(@Param("ids") List<Integer> ids);
 
-    Category findByIdOrParentId(@Param("id") Integer id, @Param("parentId") Integer parentId);
+    List<Category> findByIdOrParentId(Integer categoryId);
 
     int deleteById(@Param("id") Integer id);
 

src/main/java/com/example/copykamanotes/mapper/QuestionMapper.java

@@ -1,11 +1,102 @@
 package com.example.copykamanotes.mapper;
 
+import com.example.copykamanotes.model.dto.question.QuestionQueryParam;
 import com.example.copykamanotes.model.entity.Question;
 import org.apache.ibatis.annotations.Mapper;
+import org.apache.ibatis.annotations.Param;
 
+import java.util.List;
 import java.util.Map;
 
 @Mapper
 public interface QuestionMapper {
-    Map<Integer, Question> getQuestionMapByIds(Integer[] questionIds);
+    /**
+     * 插入一个问题对象到数据库中
+     *
+     * @param question 要插入的问题对象，包含问题的相关信息
+     * @return 插入成功返回1，否则返回0
+     */
+    int insert(Question question);
+
+    /**
+     * 根据问题ID查找问题
+     *
+     * @param questionId 问题的唯一标识符
+     * @return 返回找到的问题对象，如果没有找到则返回null
+     */
+    Question findById(@Param("questionId") Integer questionId);
+
+    /**
+     * 批量通过问题  ID查找问题
+     * 此方法允许一次性传入多个问题ID，从而批量获取问题信息
+     *
+     * @param questionIds 一个问题ID的列表，用于指定需要查找的问题
+     * @return 返回一个Question对象的列表，每个对象包含一个问题的详细信息
+     */
+    List<Question> findByIdBatch(@Param("questionIds") List<Integer> questionIds);
+
+    /**
+     * 根据查询参数获取问题列表
+     *
+     * @param queryParam 查询参数对象，包含多种可能的查询条件
+     * @param offset 分页查询的起始位置
+     * @param limit 每页返回的最大记录数
+     * @return 匹配查询条件的问题列表
+     */
+    List<Question> findByQueryParam(@Param("queryParam") QuestionQueryParam queryParam,
+                                    @Param("offset") int offset,
+                                    @Param("limit") int limit);
+
+    /**
+     * 根据关键字搜索问题
+     *
+     * @param keyword 关键字，用于匹配问题标题或内容
+     * @return 匹配关键字的问题列表
+     */
+    List<Question> findByKeyword(@Param("keyword") String keyword);
+
+    /**
+     * 更新问题
+     * @param question 问题对象，包含要更新的问题信息
+     * @return 更新成功返回1，否则返回0
+     */
+    int update(@Param("question") Question question);
+
+    /**
+     * 更新问题的浏览次数
+     * @param questionId 问题ID
+     * @return 更新成功返回1，否则返回0
+     */
+    int incrementViewCount(@Param("questionId") Integer questionId);
+
+    /**
+     * 根据查询参数统计问题的数量
+     *
+     * @param queryParam 查询参数对象，包含多个查询条件
+     * @return 满足查询条件的问题数量
+     */
+    int countByQueryParam(@Param("queryParam") QuestionQueryParam queryParam);
+
+    /**
+     * 根据问题ID删除问题
+     *
+     * @param questionId 需要删除的问题的ID
+     */
+    int deleteById(Integer questionId);
+
+    /**
+     * 根据分类ID删除相关记录
+     * 此方法旨在删除与给定分类ID 关联的实体
+     *
+     * @param categoryId 分类ID，用于标识要删除的记录
+     */
+    int deleteByCategoryId(Integer categoryId);
+
+    /**
+     * 批量删除指定分类ID的实体
+     * 通过分类ID列表来删除实体，主要用于批量操作场景
+     *
+     * @param categoryIds 分类ID列表，用于指定待删除实体的分类
+     */
+    int deleteByCategoryIdBatch(@Param("categoryIds") List<Integer> categoryIds);
 }

src/main/java/com/example/copykamanotes/model/dto/category/CreateCategoryBody.java

@@ -0,0 +1,21 @@
+package com.example.copykamanotes.model.dto.category;
+
+import lombok.Data;
+import org.hibernate.validator.constraints.Length;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
+@Data
+public class CreateCategoryBody {
+    @NotBlank(message = "name 不能为空")
+    @NotNull(message = "name 不能为空")
+    @Length(max = 32, min = 1, message = "name 长度在 1 - 32 之间")
+    private String name;
+
+    @NotNull(message = "parentCategoryId 不能为空")
+    @Min(value = 0, message = "parentCategoryId 必须为正整数")
+    private Integer parentCategoryId;
+
+}

src/main/java/com/example/copykamanotes/model/dto/category/UpdateCategoryBody.java

@@ -0,0 +1,15 @@
+package com.example.copykamanotes.model.dto.category;
+
+import lombok.Data;
+import org.hibernate.validator.constraints.Length;
+
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
+@Data
+public class UpdateCategoryBody {
+    @NotBlank(message = "name 不能为空")
+    @NotNull(message = "name 不能为空")
+    @Length(max = 32, min = 1, message = "name 长度在 1 - 32 之间")
+    private String name;
+}

src/main/java/com/example/copykamanotes/model/dto/collection/CollectionQueryParams.java

@@ -0,0 +1,16 @@
+package com.example.copykamanotes.model.dto.collection;
+
+import lombok.Data;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotNull;
+
+@Data
+public class CollectionQueryParams {
+    @NotNull(message = "creatorId 不能为空")
+    @Min(value = 1, message = "creatorId 必须为正整数")
+    private Long creatorId;
+
+    @Min(value = 1, message = "noteId 必须为正整数")
+    private Integer noteId;
+}

src/main/java/com/example/copykamanotes/model/dto/collection/CreateCollectionBody.java

@@ -0,0 +1,14 @@
+package com.example.copykamanotes.model.dto.collection;
+
+import lombok.Data;
+
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
+@Data
+public class CreateCollectionBody {
+    @NotNull(message = "name 不能为空")
+    @NotBlank(message = "name 不能为空")
+    private String name;
+    private String description;
+}

src/main/java/com/example/copykamanotes/model/dto/collection/UpdateCollectionBody.java

@@ -0,0 +1,27 @@
+package com.example.copykamanotes.model.dto.collection;
+
+import lombok.Data;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotEmpty;
+import javax.validation.constraints.NotNull;
+import javax.validation.constraints.Pattern;
+
+@Data
+public class UpdateCollectionBody {
+    @Min(value = 1, message = "noteId 必须为正整数")
+    private Integer noteId;
+
+    private UpdateItem[] collections;
+
+    @Data
+    public static class UpdateItem {
+        @Min(value = 1, message = "collectionId 必须为正整数")
+        private Integer collectionId;
+        // 必须为 create 或者 delete
+        @NotNull(message = "action 不能为空")
+        @NotEmpty(message = "action 不能为空")
+        @Pattern(regexp = "create|delete", message = "action 必须为 create 或者 delete")
+        private String action;
+    }
+}

src/main/java/com/example/copykamanotes/model/dto/comment/CreateCommentRequest.java

@@ -0,0 +1,29 @@
+package com.example.copykamanotes.model.dto.comment;
+
+import lombok.Data;
+
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
+/**
+ * 创建评论请求
+ */
+@Data
+public class CreateCommentRequest {
+    /**
+     * 笔记ID
+     */
+    @NotNull(message = "笔记ID不能为空")
+    private Integer noteId;
+
+    /**
+     * 父评论ID
+     */
+    private Integer parentId;
+
+    /**
+     * 评论内容
+     */
+    @NotBlank(message = "评论内容不能为空")
+    private String content;
+}

src/main/java/com/example/copykamanotes/model/dto/comment/UpdateCommentRequest.java

@@ -0,0 +1,17 @@
+package com.example.copykamanotes.model.dto.comment;
+
+import lombok.Data;
+
+import javax.validation.constraints.NotBlank;
+
+/**
+ * 更新评论请求
+ */
+@Data
+public class UpdateCommentRequest {
+    /**
+     * 评论内容
+     */
+    @NotBlank(message = "评论内容不能为空")
+    private String content;
+}

src/main/java/com/example/copykamanotes/model/dto/message/MessageQueryParams.java

@@ -0,0 +1,53 @@
+package com.example.copykamanotes.model.dto.message;
+
+import lombok.Data;
+import javax.validation.constraints.Min;
+import java.time.LocalDateTime;
+
+/**
+ * 消息查询参数
+ */
+@Data
+public class MessageQueryParams {
+    /**
+     * 消息类型
+     */
+    private String type;
+
+    /**
+     * 是否已读
+     */
+    private Boolean isRead;
+
+    /**
+     * 开始时间
+     */
+    private LocalDateTime startTime;
+
+    /**
+     * 结束时间
+     */
+    private LocalDateTime endTime;
+
+    /**
+     * 当前页码，从1开始
+     */
+    @Min(value = 1, message = "页码必须大于0")
+    private Integer page = 1;
+
+    /**
+     * 每页大小
+     */
+    @Min(value = 1, message = "每页大小必须大于0")
+    private Integer pageSize = 10;
+
+    /**
+     * 排序字段，默认创建时间
+     */
+    private String sortField = "created_at";
+
+    /**
+     * 排序方向，默认降序
+     */
+    private String sortOrder = "desc";
+}

src/main/java/com/example/copykamanotes/model/dto/note/NoteHeatMapItem.java

@@ -1,12 +0,0 @@
-package com.example.copykamanotes.model.dto.note;
-
-import lombok.Data;
-
-import java.time.LocalDate;
-
-@Data
-public class NoteHeatMapItem {
-    private LocalDate data;
-    private Integer count;
-    private Integer rank;
-}

src/main/java/com/example/copykamanotes/model/dto/note/NoteRankListItem.java

@@ -1,8 +0,0 @@
-package com.example.copykamanotes.model.dto.note;
-
-import lombok.Data;
-
-@Data
-public class NoteRankListItem {
-
-}

src/main/java/com/example/copykamanotes/model/dto/note/Top3Count.java

@@ -1,10 +0,0 @@
-package com.example.copykamanotes.model.dto.note;
-
-import lombok.Data;
-
-@Data
-public class Top3Count {
-    private Integer lastMonthTop3Count;
-    private Integer thisMonthTop3Count;
-}
-

src/main/java/com/example/copykamanotes/model/dto/notification/NotificationDTO.java

@@ -0,0 +1,14 @@
+package com.example.copykamanotes.model.dto.notification;
+
+import lombok.Data;
+
+import javax.validation.constraints.NotEmpty;
+import javax.validation.constraints.NotNull;
+
+@Data
+public class NotificationDTO {
+    @NotEmpty(message = "content 不能为空")
+    @NotNull(message = "content 不能为空")
+    private String content;
+}
+

src/main/java/com/example/copykamanotes/model/dto/question/CreateQuestionBody.java

@@ -0,0 +1,28 @@
+package com.example.copykamanotes.model.dto.question;
+
+import lombok.Data;
+import org.hibernate.validator.constraints.Length;
+import org.hibernate.validator.constraints.Range;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
+@Data
+public class CreateQuestionBody {
+    @NotNull(message = "categoryId 不能为空")
+    @Min(value = 1, message = "categoryId 必须为正整数")
+    private Integer categoryId;
+
+    @NotNull(message = "title 不能为空")
+    @NotBlank(message = "title 不能为空")
+    @Length(max = 255, message = "title 长度不能超过 255")
+    private String title;
+
+    @NotNull(message = "difficulty 不能为空")
+    @Range(min = 1, max = 3, message = "difficulty 必须为 1, 2, 3")
+    private Integer difficulty;
+
+    @Length(max = 255, message = "examPoint 长度不能超过 255")
+    private String examPoint;
+}

src/main/java/com/example/copykamanotes/model/dto/question/QuestionQueryParam.java

@@ -0,0 +1,29 @@
+package com.example.copykamanotes.model.dto.question;
+
+import lombok.Data;
+
+import javax.validation.constraints.Max;
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotNull;
+import javax.validation.constraints.Pattern;
+
+@Data
+public class QuestionQueryParam {
+    @Min(value = 1, message = "categoryId 必须为正整数")
+    private Integer categoryId;
+
+    @Pattern(regexp = "^(view|difficulty)$", message = "sort 必须为 view 或 difficulty")
+    private String sort;
+
+    @Pattern(regexp = "^(asc|desc)$", message = "order 必须为 asc 或 desc")
+    private String order;
+
+    @NotNull(message = "page 不能为空")
+    @Min(value = 1, message = "page 必须为正整数")
+    private Integer page;
+
+    @NotNull(message = "pageSize 不能为空")
+    @Min(value = 1, message = "pageSize 必须为正整数")
+    @Max(value = 200, message = "pageSize 不能超过 200")
+    private Integer pageSize;
+}

src/main/java/com/example/copykamanotes/model/dto/question/SearchQuestionBody.java

@@ -0,0 +1,15 @@
+package com.example.copykamanotes.model.dto.question;
+
+import lombok.Data;
+import org.hibernate.validator.constraints.Length;
+
+import javax.validation.constraints.NotEmpty;
+import javax.validation.constraints.NotNull;
+
+@Data
+public class SearchQuestionBody {
+    @NotNull(message = "keyword 不能为空")
+    @NotEmpty(message = "keyword 不能为空")
+    @Length(min = 1, max = 32, message = "keyword 长度在 1 和 32 范围内")
+    private String keyword;
+}

src/main/java/com/example/copykamanotes/model/dto/question/UpdateQuestionBody.java

@@ -0,0 +1,34 @@
+package com.example.copykamanotes.model.dto.question;
+
+import lombok.Data;
+import org.hibernate.validator.constraints.Length;
+import org.hibernate.validator.constraints.Range;
+
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
+@Data
+public class UpdateQuestionBody {
+    /*
+     * 问题标题
+     */
+    @NotNull(message = "title 不能为空")
+    @NotBlank(message = "title 不能为空")
+    @Length(max = 255, message = "title 长度不能超过 255")
+    private String title;
+
+    /*
+     * 问题难度
+     * 1=简单，2=中等，3=困难
+     */
+    @NotNull(message = "difficulty 不能为空")
+    @Range(min = 1, max = 3, message = "difficulty 必须为 1, 2, 3")
+    private Integer difficulty;
+
+    /*
+     * 题目考点
+     */
+    @Length(max = 255, message = "examPoint 长度不能超过 255")
+    private String examPoint;
+}
+

src/main/java/com/example/copykamanotes/model/dto/questionList/CreateQuestionListBody.java

@@ -0,0 +1,26 @@
+package com.example.copykamanotes.model.dto.questionList;
+
+import lombok.Data;
+import org.hibernate.validator.constraints.Length;
+import org.hibernate.validator.constraints.Range;
+
+@Data
+public class CreateQuestionListBody {
+    /*
+     * 题单名称
+     */
+    @Length(max = 32, message = "name 长度不能超过 32")
+    private String name;
+
+    /**
+     * 题单类型
+     */
+    @Range(min = 1, max = 2, message = "type 必须为 1 或 2")
+    private Integer type;
+
+    /*
+     * 题单描述
+     */
+    @Length(max = 255, message = "description 长度不能超过 255")
+    private String description;
+}

src/main/java/com/example/copykamanotes/model/dto/questionList/UpdateQuestionListBody.java

@@ -0,0 +1,27 @@
+package com.example.copykamanotes.model.dto.questionList;
+
+
+import lombok.Data;
+import org.hibernate.validator.constraints.Length;
+import org.hibernate.validator.constraints.Range;
+
+@Data
+public class UpdateQuestionListBody {
+    /*
+     * 题单名称
+     */
+    @Length(max = 32, message = "name 长度不能超过 32")
+    private String name;
+
+    /**
+     * 题单类型
+     */
+    @Range(min = 1, max = 2, message = "type 必须为 1 或 2")
+    private Integer type;
+
+    /*
+     * 题单描述
+     */
+    @Length(max = 255, message = "description 长度不能超过 255")
+    private String description;
+}

src/main/java/com/example/copykamanotes/model/dto/questionListItem/CreateQuestionListItemBody.java

@@ -0,0 +1,17 @@
+package com.example.copykamanotes.model.dto.questionListItem;
+
+import lombok.Data;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotNull;
+
+@Data
+public class CreateQuestionListItemBody {
+    @NotNull(message = "questionListId 不能为空")
+    @Min(value = 1, message = "questionListId 必须为正整数")
+    private Integer questionListId;
+
+    @NotNull(message = "questionId 不能为空")
+    @Min(value = 1, message = "questionId 必须为正整数")
+    private Integer questionId;
+}

src/main/java/com/example/copykamanotes/model/dto/questionListItem/QuestionListItemQueryParams.java

@@ -0,0 +1,23 @@
+package com.example.copykamanotes.model.dto.questionListItem;
+
+
+import lombok.Data;
+import org.hibernate.validator.constraints.Range;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotNull;
+
+@Data
+public class QuestionListItemQueryParams {
+    @NotNull(message = "questionListId 不能为空")
+    @Min(value = 1, message = "questionListId 必须为正整数")
+    private Integer questionListId;
+
+    @NotNull(message = "page 不能为空")
+    @Min(value = 1, message = "page 必须为正整数")
+    private Integer page;
+
+    @NotNull(message = "pageSize 不能为空")
+    @Range(min = 1, max = 100, message = "pageSize 必须为 1 到 100 之间的整数")
+    private Integer pageSize;
+}

src/main/java/com/example/copykamanotes/model/dto/questionListItem/SortQuestionListItemBody.java

@@ -0,0 +1,17 @@
+package com.example.copykamanotes.model.dto.questionListItem;
+
+import lombok.Data;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotNull;
+import java.util.List;
+
+@Data
+public class SortQuestionListItemBody {
+    @NotNull(message = "questionListId 不能为空")
+    @Min(value = 1, message = "questionListId 必须为正整数")
+    private Integer questionListId;
+
+    @NotNull(message = "questionListItemIds 不能为空")
+    private List<Integer> questionIds;
+}

src/main/java/com/example/copykamanotes/model/enums/questionList/QuestionListType.java

@@ -0,0 +1,15 @@
+package com.example.copykamanotes.model.enums.questionList;
+
+import lombok.Getter;
+
+@Getter
+public enum QuestionListType {
+    COMMON(1, "普通题单"),
+    TRAINING_CAMP(2, "训练营题单");
+    private final Integer type;
+    private final String desc;
+    QuestionListType(Integer type, String desc) {
+        this.type = type;
+        this.desc = desc;
+    }
+}

src/main/java/com/example/copykamanotes/service/CategoryService.java

@@ -1,4 +1,41 @@
 package com.example.copykamanotes.service;
 
+import com.example.copykamanotes.model.base.ApiResponse;
+import com.example.copykamanotes.model.base.EmptyVO;
+import com.example.copykamanotes.model.dto.category.CreateCategoryBody;
+import com.example.copykamanotes.model.dto.category.UpdateCategoryBody;
+import com.example.copykamanotes.model.vo.category.CategoryVO;
+import com.example.copykamanotes.model.vo.category.CreateCategoryVO;
+
+import java.util.List;
+
 public interface CategoryService {
+    /**
+     * 构建分类树
+     * @return 分类树
+     */
+    List<CategoryVO> buildCategoryTree();
+
+    /**
+     * 获取所有分类
+     * @return 所有分类
+     */
+    ApiResponse<List<CategoryVO>> categoryList();
+
+    /**
+     * 删除分类
+     * @param id 分类id
+     * @return
+     */
+    ApiResponse<EmptyVO> deleteCategory(Integer id);
+
+    /**
+     * 新增分类
+     * @param categoryBody 分类
+     * @return
+     */
+    ApiResponse<CreateCategoryVO> createCategory(CreateCategoryBody categoryBody);
+
+    ApiResponse<EmptyVO> updateCategory(Integer id, UpdateCategoryBody updateCategoryBody);
+
 }

src/main/java/com/example/copykamanotes/service/NoteService.java

@@ -1,13 +1,9 @@
 package com.example.copykamanotes.service;
 
-import com.example.copykamanotes.mapper.NoteMapper;
 import com.example.copykamanotes.model.base.ApiResponse;
 import com.example.copykamanotes.model.base.EmptyVO;
 import com.example.copykamanotes.model.dto.note.*;
-import com.example.copykamanotes.model.vo.note.CreateNoteVO;
+import com.example.copykamanotes.model.vo.note.*;
-import com.example.copykamanotes.model.vo.note.DownloadNoteVO;
-import com.example.copykamanotes.model.vo.note.NoteVO;
-import org.springframework.beans.factory.annotation.Autowired;
 
 import java.util.List;
 

src/main/java/com/example/copykamanotes/service/impl/CategoryServiceImpl.java

@@ -0,0 +1,128 @@
+package com.example.copykamanotes.service.impl;
+
+import com.example.copykamanotes.mapper.CategoryMapper;
+import com.example.copykamanotes.mapper.QuestionMapper;
+import com.example.copykamanotes.model.base.ApiResponse;
+import com.example.copykamanotes.model.base.EmptyVO;
+import com.example.copykamanotes.model.dto.category.CreateCategoryBody;
+import com.example.copykamanotes.model.dto.category.UpdateCategoryBody;
+import com.example.copykamanotes.model.entity.Category;
+import com.example.copykamanotes.model.vo.category.CategoryVO;
+import com.example.copykamanotes.model.vo.category.CreateCategoryVO;
+import com.example.copykamanotes.service.CategoryService;
+import com.example.copykamanotes.utils.ApiResponseUtils;
+import org.springframework.beans.BeanUtils;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+@Service
+public class CategoryServiceImpl implements CategoryService {
+
+    @Autowired
+    private CategoryMapper categoryMapper;
+
+
+    @Autowired
+    private QuestionMapper questionMapper;
+
+    @Override
+    public ApiResponse<EmptyVO> updateCategory(Integer id, UpdateCategoryBody updateCategoryBody) {
+        Category category = categoryMapper.findById(id);
+
+        if (category == null) {
+            return ApiResponseUtils.error("分类 Id 不存在");
+        }
+
+        category.setName(updateCategoryBody.getName());
+
+        try {
+            categoryMapper.update(category);
+            return ApiResponseUtils.success("更新分类成功");
+        } catch (Exception e) {
+            return ApiResponseUtils.error("更新分类失败");
+        }
+    }
+
+    @Override
+    public List<CategoryVO> buildCategoryTree() {
+        List<Category> categories = categoryMapper.categoryList();
+
+        Map<Integer, CategoryVO> categoryMap = new HashMap<>();
+
+        categories.forEach(category -> {
+            if (category.getParentCategoryId() == 0) {
+                CategoryVO categoryVO = new CategoryVO();
+                BeanUtils.copyProperties(category, categoryVO);
+                categoryVO.setChildren(new ArrayList<>());
+                categoryMap.put(category.getCategoryId(), categoryVO);
+            } else {
+                CategoryVO.ChildrenCategoryVO childrenCategoryVO = new CategoryVO.ChildrenCategoryVO();
+                BeanUtils.copyProperties(category, childrenCategoryVO);
+
+                CategoryVO parentCategory = categoryMap.get(category.getParentCategoryId());
+                if (parentCategory != null) {
+                    parentCategory.getChildren().add(childrenCategoryVO);
+                }
+            }
+        });
+
+        return new ArrayList<>(categoryMap.values());
+    }
+
+    @Override
+    public ApiResponse<List<CategoryVO>> categoryList() {
+        return ApiResponseUtils.success("获取分类列表成功", buildCategoryTree());
+    }
+
+    @Override
+    public ApiResponse<EmptyVO> deleteCategory(Integer id) {
+        List<Category> categories = categoryMapper.findByIdOrParentId(id);
+
+        if (categories.isEmpty()) {
+            return ApiResponseUtils.error("分类 Id 非法");
+        }
+
+        List<Integer> categoryIds = categories.stream().map(Category::getCategoryId).toList();
+
+        try {
+            int deleteCount = categoryMapper.deleteByIdBatch(categoryIds);
+            if (deleteCount != categories.size()) {
+                throw new RuntimeException("删除分类失败");
+            }
+
+            questionMapper.deleteByCategoryIdBatch(categoryIds);
+            return ApiResponseUtils.success("删除分类成功");
+        } catch (Exception e) {
+            throw new RuntimeException("删除分类失败");
+        }
+    }
+
+    @Override
+    public ApiResponse<CreateCategoryVO> createCategory(CreateCategoryBody createCategoryBody) {
+
+        if (createCategoryBody.getParentCategoryId() != 0) {
+            Category parent = categoryMapper.findById(createCategoryBody.getParentCategoryId());
+            if (parent == null) {
+                return ApiResponseUtils.error("父分类 Id 不存在");
+            }
+        }
+
+        Category category = new Category();
+        BeanUtils.copyProperties(createCategoryBody, category);
+
+        try {
+            categoryMapper.insert(category);
+            CreateCategoryVO createCategoryVO = new CreateCategoryVO();
+            createCategoryVO.setCategoryId(category.getCategoryId());
+            return ApiResponseUtils.success("创建分类成功", createCategoryVO);
+
+        } catch (Exception e) {
+            return ApiResponseUtils.error("创建分类失败");
+        }
+    }
+}

src/main/java/com/example/copykamanotes/service/impl/NoteServiceImpl.java

@@ -8,9 +8,7 @@ import com.example.copykamanotes.model.dto.note.*;
 import com.example.copykamanotes.model.entity.Note;
 import com.example.copykamanotes.model.entity.Question;
 import com.example.copykamanotes.model.entity.User;
-import com.example.copykamanotes.model.vo.note.CreateNoteVO;
+import com.example.copykamanotes.model.vo.note.*;
-import com.example.copykamanotes.model.vo.note.DownloadNoteVO;
-import com.example.copykamanotes.model.vo.note.NoteVO;
 import com.example.copykamanotes.scope.RequestScopeData;
 import com.example.copykamanotes.service.NoteLikeService;
 import com.example.copykamanotes.service.NoteService;