因为项目业务需要，特此写出此仿QQ空间的评论功能，项目如下图所示，records下的是一级评论
里面的commentList是二级评论，前端根据此数据格式渲染即可
表结构如下，其中father_id与reply_user_id默认为0，由于我是一张表，所以这两个字段用于区分是一级评论还是二级评论
实体类如下，其中有@TableField(exist = false)注解的都是虚拟字段，这里就不贴出用户表的实体类了。
import com.baomidou.mybatisplus.annotation.*;import java.util.Date;import com.baomidou.mybatisplus.extension.activerecord.Model;import com.fasterxml.jackson.annotation.JsonFormat;import lombok.Data;import java.io.Serializable;import java.util.List;/*** <p>* 评论* </p>** @author Mybatis-plus* @since -07-26*/@Data@TableName(resultMap = "BaseResultMap")public class Comment extends Model<Comment> implements Serializable {private static final long serialVersionUID = 1L;/*** 评论ID*/@TableId(value = "comment_id",type = IdType.AUTO)private Long commentId;/*** 所属帖子ID*/private Long postId;/*** 内容*/private String content;/*** 时间*/@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone="GMT+8")@TableField(fill = FieldFill.INSERT)private Date createTime;/*** 评论人ID(当前用户)*/private Long activeUserId;/*** 所属贴主ID*/private Long posterId;/*** 已读，未读*/private Integer readState;/*** 所属父评论ID*/private Long fatherId;/*** 被回复人ID*/private Long replyUserId;/*** 当前用户用户名*/@TableField(exist = false)private String userName;/*** 被回复人用户名*/@TableField(exist = false)private String replyUserName;/*** 当前用户头像*/@TableField(exist = false)private String headPhoto;/*** 被回复人用户头像*/@TableField(exist = false)private String replyHeadPhoto;/*** 子评论展示状态*/@TableField(exist = false)private boolean commentListState;/*** 子评论列表*/@TableField(exist = false)private List<Comment> commentList;}
mapper.xml如下
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE mapper PUBLIC "-///DTD Mapper 3.0//EN" "mybatis-3-mapper.dtd"><mapper namespace="com.mentMapper"><resultMap id="BaseResultMap" type="com.ment"><id property="commentId" column="comment_id"></id><id property="postId" column="post_id"></id><id property="content" column="content"></id><id property="createTime" column="create_time"></id><id property="activeUserId" column="active_user_id"></id><id property="posterId" column="poster_id"></id><id property="readState" column="read_state"></id><id property="fatherId" column="father_id"></id><id property="replyUserId" column="reply_user_id"></id></resultMap></mapper>
serviceImpl类如下，这里一级评论和二级评论调用的接口是同一个，传的东西不同
一级评论需要前端传 帖子ID 评论内容 父评论ID 和 被回复人ID 数据库默认是0 无需传
二级评论需要前端传 帖子ID 评论内容 被评论人ID 评论的ID 把 评论的ID set 到 父评论ID里 即 father_id 字段
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;import com.baomidou.mybatisplus.core.metadata.IPage;import com.baomidou.mybatisplus.extension.plugins.pagination.Page;import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;import com.jfs1010.mapper.PostMapper;import com.jfs1010.mapper.UserMapper;import com.ment;import com.mentMapper;import com.jfs1010.pojo.Post;import com.jfs1010.pojo.User;import com.mentService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import java.util.List;/*** <p>* 服务实现类* </p>** @author Mybatis-plus* @since -07-26*/@Servicepublic class CommentServiceImpl extends ServiceImpl<CommentMapper, Comment> implements CommentService {@Autowired(required = false)private CommentMapper commentMapper;@Autowired(required = false)private UserMapper userMapper;@Autowired(required = false)private PostMapper postMapper;/*** 发布评论(包括一级二级)** @param comment* @return*/@Overridepublic int createComment(Comment comment) {//获取当前用户Post post = new Post();post.setPostId(comment.getPostId());//收藏数+1post.setCommentNum(postMapper.selectById(comment.getPostId()).getCommentNum()+1);postMapper.updateById(post);//这里获得当前用户的ID，由于我后台还没写好，故强行获取comment.setActiveUserId(userMapper.selectOne(new QueryWrapper<User>().eq("user_name", "小兰")).getUserId());return commentMapper.insert(comment);}/*** 查询出所有的一级评论和二级评论，并且与之对应* 一级与二级区分* 一级 post_id father_id = 0 reply_user_id = 0* 二级 post_id father_id = comment_id* @param postId* @param curr* @param limit* @return*/@Overridepublic IPage<Comment> findAllComment(Long postId, Integer curr, Integer limit) {//查出所有的一级评论QueryWrapper<Comment> queryWrapper = new QueryWrapper<>();queryWrapper.eq("post_id",postId).eq("father_id",0).eq("reply_user_id",0).orderByDesc("create_time");Page<Comment> page = new Page<>(curr, limit);IPage<Comment> listMaps = commentMapper.selectPage(page, queryWrapper);//根据评论人的ID获取用户名和头像User user;for (int i = 0; i < listMaps.getRecords().size(); i++) {Comment res = listMaps.getRecords().get(i);user = userMapper.selectById(res.getActiveUserId());res.setUserName(user.getUserName());res.setHeadPhoto(user.getHeadPhoto());//二级评论展示状态，用于前端实现逻辑分页res.setCommentListState(false);//存放二级评论QueryWrapper<Comment> queryWrapperTwo = new QueryWrapper<>();queryWrapperTwo.eq("post_id",postId).eq("father_id",res.getCommentId()).orderByDesc("create_time");//修改二级评论里面的用户名和头像List<Comment> commentList = commentMapper.selectList(queryWrapperTwo);for (int j = 0;j<commentList.size();j++){Comment twoRes = commentList.get(j);user = userMapper.selectById(twoRes.getActiveUserId());//提问者用户名和头像twoRes.setUserName(user.getUserName());twoRes.setHeadPhoto(user.getHeadPhoto());//回答者用户名和头像twoRes.setReplyUserName(userMapper.selectById(twoRes.getReplyUserId()).getUserName());twoRes.setReplyHeadPhoto(userMapper.selectById(twoRes.getReplyUserId()).getHeadPhoto());}//把二级评论放到一级评论里面res.setCommentList(commentList);}return listMaps;}}
至此完成评论功能，Controller的代码我就不贴出来了。
