本篇内容介绍了“SpringBoot如何实现无限级评论回复功能”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
1 数据库表结构设计
表结构:
CREATE TABLE `comment` ( `id` bigint(18) NOT NULL AUTO_INCREMENT, `parent_id` bigint(18) NOT NULL DEFAULT '0', `content` text NOT NULL COMMENT '内容', `author` varchar(20) NOT NULL COMMENT '评论人', `create_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '评论时间', PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8mb4;数据添加:
INSERT INTO `comment` (`id`, `parent_id`, `content`, `author`, `create_time`) VALUES (1, 0, '这是评论1', '吴名氏', '2023-02-20 17:11:16');INSERT INTO `comment` (`id`, `parent_id`, `content`, `author`, `create_time`) VALUES (2, 1, '我回复了第一条评论', '吴名氏', '2023-02-20 17:12:00');INSERT INTO `comment` (`id`, `parent_id`, `content`, `author`, `create_time`) VALUES (3, 2, '我回复了第一条评论的第一条回复', '吴名氏', '2023-02-20 17:12:13');INSERT INTO `comment` (`id`, `parent_id`, `content`, `author`, `create_time`) VALUES (4, 2, '我回复了第一条评论的第二条回复', '吴名氏', '2023-02-21 09:23:14');INSERT INTO `comment` (`id`, `parent_id`, `content`, `author`, `create_time`) VALUES (5, 0, '这是评论2', '吴名氏', '2023-02-21 09:41:02');INSERT INTO `comment` (`id`, `parent_id`, `content`, `author`, `create_time`) VALUES (6, 3, '我回复了第一条评论的第一条回复的第一条回复', '吴名氏', '2023-02-21 09:56:27');添加后的数据:
2 方案一
方案一先返回评论列表,再根据评论id返回回复列表,以此循环,具体代码下文进行展示
2.1 控制层CommentOneController.java
@Slf4j@RestController@RequestMapping("/one/comment")public class CommentOneController { @Resource private CommentService commentService; @GetMapping("/") public List<Comment> getList() { return commentService.getList(); } @GetMapping("/{id}") public Comment getCommentById(@PathVariable Long id) { return commentService.getById(id); } @GetMapping("/parent/{parentId}") public List<Comment> getCommentByParentId(@PathVariable Long parentId) { return commentService.getCommentByParentId(parentId); } @PostMapping("/") public void addComment(@RequestBody Comment comment) { commentService.addComment(comment); } }2.2 service类CommentService.java
public interface CommentService { List<Comment> getCommentByParentId(Long parentId); void addComment(Comment comment); Comment getById(Long id); List<Comment> getList();}2.3 service实现类CommentServiceImpl.java
@Servicepublic class CommentServiceImpl implements CommentService{ @Resource private CommentMapper baseMapper; @Override public List<Comment> getCommentByParentId(Long parentId) { QueryWrapper<Comment> queryWrapper = new QueryWrapper<>(); queryWrapper.eq("parent_id", parentId); return baseMapper.selectList(queryWrapper); } @Override public void addComment(Comment comment) { baseMapper.insert(comment); } @Override public Comment getById(Long id) { return baseMapper.selectById(id); } @Override public List<Comment> getList() { return baseMapper.selectList(new QueryWrapper<Comment>().lambda().eq(Comment::getParentId, 0)); } }2.4 数据库持久层类CommentMapper.java
@Repositorypublic interface CommentMapper extends BaseMapper<Comment> { }2.5 实体类Comment.java
@Data@TableName("comment")public class Comment { @TableId(type = IdType.AUTO) private Long id; private Long parentId; private String content; private String author; @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8") private Date createTime;}2.6 使用Postman请求接口,查看返回数据
1 请求评论列表接口(本地的url为:http://localhost:8081/one/comment/ ,GET请求),请求结果如图
2 根据评论id(或者回复id)返回回复列表(本地url为:http://localhost:8081/one/comment/parent/1 ,GET请求),请求结果如图
3 方案二
方案二采用的是将数据装到一个类似树的数据结构,然后返回,数据如果多的话,可以根据评论列表进行分页
3.1 控制层CommentTwoController.java
@Slf4j@RestController@RequestMapping("/two/comment")public class CommentTwoController { @Resource private CommentService commentService; @GetMapping("/") public List<CommentDTO> getAllComments() { return commentService.getAllComments(); } @PostMapping("/") public void addComment(@RequestBody Comment comment) { commentService.addComment(comment); }}3.2 service类CommentService.java
public interface CommentService { void addComment(Comment comment); void setChildren(CommentDTO commentDTO); List<CommentDTO> getAllComments();}3.3 service实现类CommentServiceImpl.java
@Servicepublic class CommentServiceImpl implements CommentService{ @Resource private CommentMapper baseMapper; @Override public void addComment(Comment comment) { baseMapper.insert(comment); } @Override public List<CommentDTO> getAllComments() { List<CommentDTO> rootComments = baseMapper.findByParentId(0L); rootComments.forEach(this::setChildren); return rootComments; } @Override public void setChildren(CommentDTO commentDTO){ List<CommentDTO> children = baseMapper.findByParentId(commentDTO.getId()); if (!children.isEmpty()) { commentDTO.setChildren(children); children.forEach(this::setChildren); } } }3.4 数据库持久层类CommentMapper.java
@Repositorypublic interface CommentMapper extends BaseMapper<Comment> { @Select("SELECT id, parent_id as parentId, content, author, create_time as createTime FROM comment WHERE parent_id = #{parentId}") List<CommentDTO> findByParentId(Long parentId); }3.5 实体类CommentDTO.java
@Datapublic class CommentDTO { private Long id; private Long parentId; private String content; private String author; private List<CommentDTO> children; @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8") private Date createTime; }3.6 使用Postman请求接口,查看返回数据
1 通过递归的方式以树的数据结构返回(本地url为:http://localhost:8081/two/comment/ ,GET请求),请求结果如图
返回的json格式如图:
[ { "id": 1, "parentId": 0, "content": "这是评论1", "author": "吴名氏", "children": [ { "id": 2, "parentId": 1, "content": "我回复了第一条评论", "author": "吴名氏", "children": [ { "id": 3, "parentId": 2, "content": "我回复了第一条评论的第一条回复", "author": "吴名氏", "children": [ { "id": 6, "parentId": 3, "content": "我回复了第一条评论的第一条回复的第一条回复", "author": "吴名氏", "children": null, "createTime": "2023-02-21 09:56:27" } ], "createTime": "2023-02-20 17:12:13" }, { "id": 4, "parentId": 2, "content": "我回复了第一条评论的第二条回复", "author": "吴名氏", "children": null, "createTime": "2023-02-21 09:23:14" } ], "createTime": "2023-02-20 17:12:00" } ], "createTime": "2023-02-20 17:11:16" }, { "id": 5, "parentId": 0, "content": "这是评论2", "author": "吴名氏", "children": null, "createTime": "2023-02-21 09:41:02" }]4 方案三
方案三是将所有数据用递归的SQL查出来,再把数据解析成树,返回结果,适合数据较少的情况下,且MySQL版本需要在8.0以上
4.1 控制层CommentThreeController.java
@Slf4j@RestController@RequestMapping("/three/comment")public class CommentThreeController { @Resource private CommentService commentService; @GetMapping("/") public List<CommentDTO> getAllCommentsBySql() { return commentService.getAllCommentsBySql(); } @PostMapping("/") public void addComment(@RequestBody Comment comment) { commentService.addComment(comment); }}4.2 service类CommentService.java
public interface CommentService { List<CommentDTO> getAllCommentsBySql(); }4.3 service实现类CommentServiceImpl.java
@Servicepublic class CommentServiceImpl implements CommentService{ @Resource private CommentMapper baseMapper; @Override public void setChildren(CommentDTO commentDTO){ List<CommentDTO> children = baseMapper.findByParentId(commentDTO.getId()); if (!children.isEmpty()) { commentDTO.setChildren(children); children.forEach(this::setChildren); } } }4.4 数据库持久层类CommentMapper.java
@Repositorypublic interface CommentMapper extends BaseMapper<Comment> { @DS("localhost80") List<CommentDTO> getAllCommentsBySql(); }4.5 实体类Comment.java
@Data@TableName("comment")public class Comment { @TableId(type = IdType.AUTO) private Long id; private Long parentId; private String content; private String author; @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8") private Date createTime; private Integer level;}4.6 使用Postman请求接口,查看返回数据
1 通过递归的方式以树的数据结构返回(本地url为:http://localhost:8081/three/comment/ ,GET请求),请求结果如图
返回的json格式如图:
[ { "id": 1, "parentId": 0, "content": "这是评论1", "author": "吴名氏", "children": [ { "id": 2, "parentId": 1, "content": "我回复了第一条评论", "author": "吴名氏", "children": [ { "id": 3, "parentId": 2, "content": "我回复了第一条评论的第一条回复", "author": "吴名氏", "children": [ { "id": 6, "parentId": 3, "content": "我回复了第一条评论的第一条回复的第一条回复", "author": "吴名氏", "children": [], "createTime": "2023-02-21 09:56:27", "level": 4 } ], "createTime": "2023-02-20 17:12:13", "level": 3 }, { "id": 4, "parentId": 2, "content": "我回复了第一条评论的第二条回复", "author": "吴名氏", "children": [], "createTime": "2023-02-21 09:23:14", "level": 3 } ], "createTime": "2023-02-20 17:12:00", "level": 2 } ], "createTime": "2023-02-20 17:11:16", "level": 1 }, { "id": 5, "parentId": 0, "content": "这是评论2", "author": "吴名氏", "children": [], "createTime": "2023-02-21 09:41:02", "level": 1 }]“SpringBoot如何实现无限级评论回复功能”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注编程网网站，小编将为大家输出更多高质量的实用文章！
