Java单表实现评论回复功能
最近在写毕业设计的时候发现需要实现一个评论功能，然后看了一下掘金和csdn的评论区，如何实现评论功能？
评论功能有多种实现方式：
- 单层型
- 套娃型（多层型）
- 两层型
单层型：
套娃型：
两层型：
这个地方有个answer_id 很容易让人迷糊：是回复哪个用户的id
CREATE TABLE `tb_blog_comments` ( `id` bigint(20) UNSIGNED NOT NULL AUTO_INCREMENT COMMENT '主键', `user_id` bigint(20) UNSIGNED NOT NULL COMMENT '用户id', `blog_id` bigint(20) UNSIGNED NOT NULL COMMENT '探店id', `parent_id` bigint(20) UNSIGNED NOT NULL COMMENT '关联的1级评论id，如果是一级评论，则值为0', `answer_id` bigint(20) UNSIGNED NOT NULL COMMENT '回复的评论id', `content` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '回复的内容', `liked` int(8) UNSIGNED NULL DEFAULT 0 COMMENT '点赞数', `status` tinyint(1) UNSIGNED NULL DEFAULT 0 COMMENT '状态，0：正常，1：被举报，2：禁止查看', `create_time` timestamp(0) NOT NULL DEFAULT CURRENT_TIMESTAMP(0) COMMENT '创建时间', `update_time` timestamp(0) NOT NULL DEFAULT CURRENT_TIMESTAMP(0) ON UPDATE CURRENT_TIMESTAMP(0) COMMENT '更新时间', PRIMARY KEY (`id`) USING BTREE) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = COMPACT;SET FOREIGN_KEY_CHECKS = 1;import com.baomidou.mybatisplus.annotation.IdType;import com.baomidou.mybatisplus.annotation.TableField;import com.baomidou.mybatisplus.annotation.TableId;import com.baomidou.mybatisplus.annotation.TableName;import com.fasterxml.jackson.annotation.JsonFormat;import lombok.Data;import lombok.EqualsAndHashCode;import lombok.experimental.Accessors;import java.io.Serializable;import java.time.LocalDateTime;import java.util.List;@Data@EqualsAndHashCode(callSuper = false)@Accessors(chain = true)@TableName("tb_blog_comments")public class BlogComments implements Serializable { private static final long serialVersionUID = 1L; @TableId(value = "id", type = IdType.AUTO) private Long id; private Long userId; private Long blogId; private Long parentId; private Long answerId; private String content; private Integer liked; private Boolean status; @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss") private LocalDateTime createTime; private LocalDateTime updateTime; @TableField(exist = false) private Boolean isLike; @TableField(exist = false) List<BlogComments> children; @TableField(exist = false) private String nickName; @TableField(exist = false) private String icon; @TableField(exist = false) private String pNickName; @TableField(exist = false) private String pIcon;}- 因为有评论区有两层，所以肯定有一个parent_id，这样你才能知道你是哪个评论下面的回复内容，如果继续评论，那么那条评论的parent_id还是之前那条评论的parent_id，而不是那条子评论的id。
- 回复内容也同样是一个评论实体类，只不过是一个集合，所以用List 存储，泛型使用实体类
- 我的功能实现也用到了父评论的用户名和头像，这样可以更好看出这是谁评论的，回复给谁的评论
6.1 Sql入手
首先，我们需要知道自己需要哪些数据，返回给前端
如果你连mybatis都不会，那就看下思路吧
从这里获取到了评论表的所有数据，以及评论的人的信息，比如说昵称、头像、id，可以展示在前端
DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" ><mapper namespace="com.sky.mapper.BlogCommentsMapper"> <select id="findCommentDetail" resultType="com.sky.pojo.BlogComments"> SELECT bl.*, u.icon, u.nick_name FROM `tb_blog_comments` bl left join tb_user u on u.id = bl.user_id where bl.blog_id = #{blogId} order by bl.id desc select>mapper>对应的mapper接口
package com.sky.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;import com.sky.pojo.BlogComments;import org.apache.ibatis.annotations.Mapper;import java.util.List;@Mapperpublic interface BlogCommentsMapper extends BaseMapper<BlogComments> { List<BlogComments> findCommentDetail(Long blogId);}6.2 业务实现
- 1.首先我们需要从数据中获取所有的数据
- 2.然后我们需要找到所有的一级评论，一级评论就是最高级，他不在谁的下面，他就是最大的，我这里在添加评论的时候前端做了处理，只要是一级评论，他的paren_id = 0
- 3.然后我们需要从一级评论下面添加他下面所有的子评论
- 最主要的就是如何将父级评论的信息添加到自己的数据中？
- 4.通过子评论中的paren_id 找到父评论，然后通过子评论的answer_id == 父评论的user_id 这样就可以拿到父评论的那一条数据
- 最后通过Optional 添加到子评论的数据中
@Overridepublic Result showBlogComments(Long blogId) { // 先将数据库中的数据全部查询出来，包括评论作者的信息，昵称和头像 List<BlogComments> blogComments = blogCommentsMapper.findCommentDetail(blogId); // 获取所有的一级评论 List<BlogComments> rootComments = blogComments.stream().filter(blogComments1 -> blogComments1.getParentId() == 0).collect(Collectors.toList()); // 从一级评论中获取回复评论 for (BlogComments rootComment : rootComments) { // 回复的评论 List<BlogComments> comments = blogComments.stream() .filter(blogComment -> blogComment.getParentId().equals(rootComment.getId())) .collect(Collectors.toList()); // 回复评论中含有父级评论的信息 comments.forEach(comment -> { // 无法判断pComment是否存在，可以使用Optional Optional<BlogComments> pComment = blogComments .stream() // 获取所有的评论的回复id也就是父级id的userid，这样就可以获取到父级评论的信息 .filter(blogComment -> comment.getAnswerId().equals(blogComment.getUserId())).findFirst(); // 这里使用了Optional 只有pcomment！=null 的时候才会执行下面的代码 pComment.ifPresent(v -> { comment.setPNickName(v.getNickName()); comment.setPIcon(v.getIcon()); }); // 判断是否点赞 isBlogCommentLiked(comment); }); rootComment.setChildren(comments); // 判断是否点赞 isBlogCommentLiked(rootComment); } return Result.ok(rootComments);}因为前端代码很多，只copy关键代码
<html><body><div class="comment-list"> <div class="comment-box" style="display: block" v-for="comment in commnetList" :key="comment.id"> <div style="display:flex"> <div class="comment-icon"> <img :src="comment.icon" alt=""> div> <div class="comment-info"> <div class="comment-user"> {{comment.nickName}} div> <div style="display: flex"> {{comment.createTime}} <div style="margin-left: 42%;display: flex;"> <div @click="addCommnetLike(comment)" style="display: flex"> <svg t="1646634642977" class="icon" viewBox="0 0 1024 1024" version="1.1" xmlns="http://www.w3.org/2000/svg" p-id="2187" width="14" height="14"> <path d="M160 944c0 8.8-7.2 16-16 16h-32c-26.5 0-48-21.5-48-48V528c0-26.5 21.5-48 48-48h32c8.8 0 16 7.2 16 16v448zM96 416c-53 0-96 43-96 96v416c0 53 43 96 96 96h96c17.7 0 32-14.3 32-32V448c0-17.7-14.3-32-32-32H96zM505.6 64c16.2 0 26.4 8.7 31 13.9 4.6 5.2 12.1 16.3 10.3 32.4l-23.5 203.4c-4.9 42.2 8.6 84.6 36.8 116.4 28.3 31.7 68.9 49.9 111.4 49.9h271.2c6.6 0 10.8 3.3 13.2 6.1s5 7.5 4 14l-48 303.4c-6.9 43.6-29.1 83.4-62.7 112C815.8 944.2 773 960 728.9 960h-317c-33.1 0-59.9-26.8-59.9-59.9v-455c0-6.1 1.7-12 5-17.1 69.5-109 106.4-234.2 107-364h41.6z m0-64h-44.9C427.2 0 400 27.2 400 60.7c0 127.1-39.1 251.2-112 355.3v484.1c0 68.4 55.5 123.9 123.9 123.9h317c122.7 0 227.2-89.3 246.3-210.5l47.9-303.4c7.8-49.4-30.4-94.1-80.4-94.1H671.6c-50.9 0-90.5-44.4-84.6-95l23.5-203.4C617.7 55 568.7 0 505.6 0z" p-id="2188" :fill="comment.isLike ? '#ff6633' : '#82848a'">path> svg> {{comment.liked}} div> <div style=" display:flex"> <el-dropdown trigger="click" size="mini" placement="top" type="mini"> <i class="el-icon-more">i> <el-dropdown-menu> <el-dropdown-item><div @click="replyCommentForm(comment)"> 回复div> el-dropdown-item> <el-dropdown-item><div v-if="comment.userId == user.id" @click="deleteComment(comment.id)"> 删除div> el-dropdown-item> el-dropdown-menu> el-dropdown> div> div> div> <div style="padding: 5px 0; font-size: 14px;display: flex;"> <div> {{comment.content}} div> div> div> div> <div v-if="comment.children.length" style="padding-left: 5px;"> <div v-for="reply in comment.children" :key="reply.id" style="padding: 5px 10px"> <div style="display: flex"> <div class="comment-icon"> <img :src="reply.icon" alt=""> div> <div class="comment-info"> <div class="comment-user"> {{reply.nickName}} 回复： {{reply.pnickName}} div> <div style="display: flex"> {{reply.createTime}} <div style="margin-left: 40%;display: flex;"> <div style="display: flex" @click="addCommnetLike(reply)"> <svg t="1646634642977" class="icon" viewBox="0 0 1024 1024" version="1.1"xmlns="http://www.w3.org/2000/svg" p-id="2187" width="14" height="14"><path d="M160 944c0 8.8-7.2 16-16 16h-32c-26.5 0-48-21.5-48-48V528c0-26.5 21.5-48 48-48h32c8.8 0 16 7.2 16 16v448zM96 416c-53 0-96 43-96 96v416c0 53 43 96 96 96h96c17.7 0 32-14.3 32-32V448c0-17.7-14.3-32-32-32H96zM505.6 64c16.2 0 26.4 8.7 31 13.9 4.6 5.2 12.1 16.3 10.3 32.4l-23.5 203.4c-4.9 42.2 8.6 84.6 36.8 116.4 28.3 31.7 68.9 49.9 111.4 49.9h271.2c6.6 0 10.8 3.3 13.2 6.1s5 7.5 4 14l-48 303.4c-6.9 43.6-29.1 83.4-62.7 112C815.8 944.2 773 960 728.9 960h-317c-33.1 0-59.9-26.8-59.9-59.9v-455c0-6.1 1.7-12 5-17.1 69.5-109 106.4-234.2 107-364h41.6z m0-64h-44.9C427.2 0 400 27.2 400 60.7c0 127.1-39.1 251.2-112 355.3v484.1c0 68.4 55.5 123.9 123.9 123.9h317c122.7 0 227.2-89.3 246.3-210.5l47.9-303.4c7.8-49.4-30.4-94.1-80.4-94.1H671.6c-50.9 0-90.5-44.4-84.6-95l23.5-203.4C617.7 55 568.7 0 505.6 0z" p-id="2188" :fill="reply.isLike ? '#ff6633' : '#82848a'">path> svg> {{reply.liked}} div> <div style="display:flex"> <el-dropdown trigger="click" size="mini" placement="top" type="mini"><i class="el-icon-more">i><el-dropdown-menu> <el-dropdown-item> <div @click="replyCommentForm(reply)"> 回复 div> el-dropdown-item> <el-dropdown-item> <div v-if="reply.userId == user.id" @click="deleteComment(reply.id)"> 删除 div> el-dropdown-item>el-dropdown-menu> el-dropdown> div> div> div> <div style="padding: 5px 0; font-size: 14px;display: flex;"> <div> {{reply.content}} div> div> div> div> div> div> div> div><script> let each = function (ary, callback) { for (let i = 0, l = ary.length; i < l; i++) { if (callback(ary[i], i) === false) break } } const app = new Vue({ el: "#app", data: { util, showPopover: false, actions: [{ text: '回复', icon: '' }, { text: '删除', icon: '' }], commentsTotal: '', // 评论总数 checkCommentInputVisible: false, // 判断是否点击回复 commnetList: {}, // 评论回复列表 placeholderText: '发条友善评论吧~~', commentForm: { content: '', userId: '', blogId: '', parentId: 0, answerId: 0, }, // 评论表单 blog: {}, shop: {}, likes: [], user: {}, // 登录用户 methods: { replyCommentForm(comment) { this.placeholderText = "回复 " + comment.nickName this.checkCommentInputVisible = true; if (comment.parentId == 0) { this.commentForm.parentId = comment.id; } else { this.commentForm.parentId = comment.parentId; } this.commentForm.answerId = comment.userId; }, submitCommentForm() { this.commentForm.userId = this.user.id; this.commentForm.blogId = this.blog.id; axios.post("/blog-comments/saveBlogComment", this.commentForm) .then(res => { this.loadComments(this.blog.id); this.checkCommentInputVisible = false; }) .catch(err => this.$message.error(err)) }, loadComments(id) { axios.get("/blog-comments/showBlogComments/" + id) .then(res => { this.commnetList = res.data }) .catch(err => this.$message.err(error)) }, } script> body>html>
点赞、评论、回复、删除
如果需要源码，可以评论区留言，我天天都会看的哦！感谢！
来源地址：https://blog.csdn.net/weixin_46073538/article/details/128149632
