【Java Web】论坛帖子添加评论

• 数据层
  • 增加评论数据；
  • 修改帖子评论数量；
• 业务层
  • 处理添加评论的业务；
  • 先增加评论、在更新帖子的评论数量；
• 表现层
  • 处理添加评论数据的请求；
  • 设置添加评论的表单。

一、数据层

1.1 CommentMapper.java

package com.nowcoder.community.dao;import com.nowcoder.community.entity.Comment;
import org.apache.ibatis.annotations.Mapper;import java.util.List;@Mapperpublic interface CommentMapper {List<Comment> selectCommentsByEntity(int entityType, int entityId, int offset, int limit);int selectCountByEntity(int entityType, int entityId);int insertComment(Comment comment);
}

1.2 Comment-Mapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.nowcoder.community.dao.CommentMapper"><sql id="selectFields">id, user_id, entity_type, entity_id, target_id, content, status, create_time</sql><sql id="insertFields">user_id, entity_type, entity_id, target_id, content, status, create_time</sql><select id="selectCommentsByEntity" resultType="Comment">select <include refid="selectFields"></include>from commentwhere status = 0and entity_type = #{entityType}and entity_id = #{entityId}order by create_time asclimit #{offset}, #{limit}</select><select id="selectCountByEntity" resultType="int">select count(id)from commentwhere status = 0and entity_type = #{entityType}and entity_id = #{entityId}</select><insert id="insertComment" parameterType="Comment">insert into comment (<include refid="insertFields"></include>)values (#{userId},#{entityType},#{entityId},#{targetId},#{content},#{status},#{createTime})</insert></mapper>

1.3 DiscussPostMapper.java

package com.nowcoder.community.dao;import com.nowcoder.community.entity.DiscussPost;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;import java.util.List;@Mapper
public interface DiscussPostMapper {List<DiscussPost> selectDiscussPosts(int userId, int offset, int limit);// @Param注解用于给参数取别名,// 如果只有一个参数,并且在<if>里使用,则必须加别名.int selectDiscussPostRows(@Param("userId") int userId);// 增加帖子int insertDiscussPost(DiscussPost discussPost);DiscussPost selectDiscussPostById(int id);int updateCommentCount(int id, int commentCount);}

1.4 DiscussPostMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.nowcoder.community.dao.DiscussPostMapper"><sql id="selectFields">id, user_id, title, content, type, status, create_time, comment_count, score</sql><sql id="insertFields">user_id, title, content, type, status, create_time, comment_count, score</sql><select id="selectDiscussPosts" resultType="DiscussPost">select <include refid="selectFields"></include>from discuss_postwhere status != 2<if test="userId!=0">and user_id = #{userId}</if>order by type desc, create_time desclimit #{offset}, #{limit}</select><select id="selectDiscussPostRows" resultType="int">select count(id)from discuss_postwhere status != 2<if test="userId!=0">and user_id = #{userId}</if></select><insert id="insertDiscussPost" parameterType="DiscussPost">insert into discuss_post (<include refid="insertFields"></include>)values (#{userId},#{title},#{content},#{type},#{status},#{createTime},#{commentCount},#{score})</insert><select id="selectDiscussPostById" resultType="DiscussPost">select <include refid="selectFields"></include>from discuss_postwhere id = #{id}</select><update id="updateCommentCount">update discuss_post set comment_count = #{commentCount} where id = #{id}</update></mapper>

二、业务层

2.1 Service

package com.nowcoder.community.service;import com.nowcoder.community.dao.CommentMapper;
import com.nowcoder.community.dao.DiscussPostMapper;
import com.nowcoder.community.entity.Comment;
import com.nowcoder.community.util.CommunityConstant;
import com.nowcoder.community.util.SensitiveFilter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Isolation;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.util.HtmlUtils;import java.util.List;@Servicepublic class CommentService implements CommunityConstant{@Autowiredprivate CommentMapper commentMapper;@Autowiredprivate SensitiveFilter sensitiveFilter;@Autowiredprivate DiscussPostService discussPostService;public List<Comment> findCommentsByEntity(int entityType, int entityId, int offset, int limit){return commentMapper.selectCommentsByEntity(entityType,entityId,offset,limit);}public int findCommentCount(int entityType, int entityId){return commentMapper.selectCountByEntity(entityType,entityId);}@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)public int addComment(Comment comment){if(comment == null){throw new IllegalArgumentException("参数不能为空");}// 添加评论，过滤敏感词和html标签comment.setContent(HtmlUtils.htmlEscape(comment.getContent()));comment.setContent(sensitiveFilter.filter(comment.getContent()));int rows = commentMapper.insertComment(comment);// 更新帖子评论数量if(comment.getEntityType()==ENTITY_TYPE_POST){ // 一级评论int count = commentMapper.selectCountByEntity(comment.getEntityType(), comment.getEntityId());discussPostService.updateCommentCount(comment.getTargetId(), count);}return rows;}
}

三、表现层

3.1 Controller

package com.nowcoder.community.controller;import com.nowcoder.community.entity.Comment;
import com.nowcoder.community.entity.User;
import com.nowcoder.community.service.CommentService;
import com.nowcoder.community.service.DiscussPostService;
import com.nowcoder.community.util.HostHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;import java.util.Date;@Controller
@RequestMapping("/comment")public class CommentController {@Autowiredprivate CommentService commentService;@Autowiredprivate HostHolder hostHolder;@RequestMapping(path = "/add/{discussPostId}", method = RequestMethod.POST)public String addComment(@PathVariable("discussPostId") int discussPostId, Comment comment){// 获取用户User user = hostHolder.getUser();
//        if(user == null) return 0;comment.setUserId(user.getId());comment.setStatus(0);comment.setCreateTime(new Date());System.out.println(user.getUsername());commentService.addComment(comment);return "redirect:/discuss/detail/" + discussPostId;}}

3.2 html

<!doctype html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"><link rel="icon" href="https://static.nowcoder.com/images/logo_87_87.png"/><link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" crossorigin="anonymous"><link rel="stylesheet" th:href="@{/css/global.css}" /><link rel="stylesheet" th:href="@{/css/discuss-detail.css}" /><title>牛客网-帖子详情</title>
</head>
<body>
<div class="nk-container"><!-- 头部 --><header class="bg-dark sticky-top" th:replace="index::header"><div class="container"><!-- 导航 --><nav class="navbar navbar-expand-lg navbar-dark"><!-- logo --><a class="navbar-brand" href="#"></a><button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation"><span class="navbar-toggler-icon"></span></button><!-- 功能 --><div class="collapse navbar-collapse" id="navbarSupportedContent"><ul class="navbar-nav mr-auto"><li class="nav-item ml-3 btn-group-vertical"><a class="nav-link" href="../index.html">首页</a></li><li class="nav-item ml-3 btn-group-vertical"><a class="nav-link position-relative" href="letter.html">消息<span class="badge badge-danger">12</span></a></li><li class="nav-item ml-3 btn-group-vertical"><a class="nav-link" href="register.html">注册</a></li><li class="nav-item ml-3 btn-group-vertical"><a class="nav-link" href="login.html">登录</a></li><li class="nav-item ml-3 btn-group-vertical dropdown"><a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false"><img src="http://images.nowcoder.com/head/1t.png" class="rounded-circle" style="width:30px;"/></a><div class="dropdown-menu" aria-labelledby="navbarDropdown"><a class="dropdown-item text-center" href="profile.html">个人主页</a><a class="dropdown-item text-center" href="setting.html">账号设置</a><a class="dropdown-item text-center" href="login.html">退出登录</a><div class="dropdown-divider"></div><span class="dropdown-item text-center text-secondary">nowcoder</span></div></li></ul><!-- 搜索 --><form class="form-inline my-2 my-lg-0" action="search.html"><input class="form-control mr-sm-2" type="search" aria-label="Search" /><button class="btn btn-outline-light my-2 my-sm-0" type="submit">搜索</button></form></div></nav></div></header><!-- 内容 --><div class="main"><!-- 帖子详情 --><div class="container"><!-- 标题 --><h6 class="mb-4"><img src="http://static.nowcoder.com/images/img/icons/ico-discuss.png"/><span th:utext="${post.title}">备战春招，面试刷题跟他复习，一个月全搞定！</span><div class="float-right"><button type="button" class="btn btn-danger btn-sm">置顶</button><button type="button" class="btn btn-danger btn-sm">加精</button><button type="button" class="btn btn-danger btn-sm">删除</button></div></h6><!-- 作者 --><div class="media pb-3 border-bottom"><a href="profile.html"><img th:src="${user.headerUrl}" class="align-self-start mr-4 rounded-circle user-header" alt="用户头像" ></a><div class="media-body"><div class="mt-0 text-warning" th:utext="${user.username}">寒江雪</div><div class="text-muted mt-3">发布于 <b th:text="${#dates.format(post.createTime,'yyyy-MM-dd HH:mm:ss')}">2019-04-15 15:32:18</b><ul class="d-inline float-right"><li class="d-inline ml-2"><a href="#" class="text-primary">赞 11</a></li><li class="d-inline ml-2">|</li><li class="d-inline ml-2"><a href="#replyform" class="text-primary">回帖 <i th:text="${post.commentCount}">7</i></a></li></ul></div></div></div><!-- 正文 --><div class="mt-4 mb-3 content" th:utext="${post.content}">金三银四的金三已经到了，你还沉浸在过年的喜悦中吗？如果是，那我要让你清醒一下了：目前大部分公司已经开启了内推，正式网申也将在3月份陆续开始，金三银四，春招的求职黄金时期已经来啦！！！再不准备，作为19应届生的你可能就找不到工作了。。。作为20届实习生的你可能就找不到实习了。。。现阶段时间紧，任务重，能做到短时间内快速提升的也就只有算法了，那么算法要怎么复习？重点在哪里？常见笔试面试算法题型和解题思路以及最优代码是怎样的？跟左程云老师学算法，不仅能解决以上所有问题，还能在短时间内得到最大程度的提升！！！</div></div><!-- 回帖 --><div class="container mt-3"><!-- 回帖数量 --><div class="row"><div class="col-8"><h6><b class="square"></b> <i th:text="${post.commentCount}">30</i>条回帖</h6></div><div class="col-4 text-right"><a href="#replyform" class="btn btn-primary btn-sm">&nbsp;&nbsp;回&nbsp;&nbsp;帖&nbsp;&nbsp;</a></div></div><!-- 回帖列表 --><ul class="list-unstyled mt-4"><li class="media pb-3 pt-3 mb-3 border-bottom" th:each="cvo:${comments}"><a href="profile.html"><img th:src="${cvo.user.headerUrl}" class="align-self-start mr-4 rounded-circle user-header" alt="用户头像" ></a><div class="media-body"><div class="mt-0"><span class="font-size-12 text-success" th:utext="${cvo.user.username}">掉脑袋切切</span><span class="badge badge-secondary float-right floor"><i th:text="${page.offset + cvoStat.count}">1</i>#</span></div><div class="mt-2" th:utext="${cvo.comment.content}">这开课时间是不是有点晚啊。。。</div><div class="mt-4 text-muted font-size-12"><span>发布于 <b th:text="${#dates.format(cvo.comment.createTime,'yyyy-MM-dd HH:mm:ss')}">2019-04-15 15:32:18</b></span><ul class="d-inline float-right"><li class="d-inline ml-2"><a href="#" class="text-primary">赞(1)</a></li><li class="d-inline ml-2">|</li><li class="d-inline ml-2"><a href="#" class="text-primary">回复(<i th:text="${cvo.replyCount}">2</i>)</a></li></ul></div><!-- 回复列表 --><ul class="list-unstyled mt-4 bg-gray p-3 font-size-12 text-muted"><li class="pb-3 pt-3 mb-3 border-bottom" th:each="rvo:${cvo.replys}"><div><span th:if="${rvo.target==null}"><b class="text-info" th:text="${rvo.user.username}">寒江雪</b>:&nbsp;&nbsp;</span><span th:if="${rvo.target!=null}"><i class="text-info" th:text="${rvo.user.username}">Sissi</i> 回复<b class="text-info" th:text="${rvo.target.username}">寒江雪</b>:&nbsp;&nbsp;</span><span th:utext="${rvo.reply.content}">这个是直播时间哈，觉得晚的话可以直接看之前的完整录播的~</span></div><div class="mt-3"><span th:text="${#dates.format(rvo.reply.createTime,'yyyy-MM-dd HH:mm:ss')}">2019-04-15 15:32:18</span><ul class="d-inline float-right"><li class="d-inline ml-2"><a href="#" class="text-primary">赞(1)</a></li><li class="d-inline ml-2">|</li><li class="d-inline ml-2"><a th:href="|#huifu-${rvoStat.count}|" data-toggle="collapse" class="text-primary">回复</a></li></ul><div th:id="|huifu-${rvoStat.count}|" class="mt-4 collapse"><form method="post" th:action="@{|/comment/add/${post.id}|}"><div><input type="text" class="input-size" name="content" th:placeholder="|回复${rvo.user.username}|"/><input type="hidden" name="entityType" value="2"><input type="hidden" name="entityId" th:value="${cvo.comment.id}"><input type="hidden" name="targetId" th:value="${rvo.user.id}"></div><div class="text-right mt-2"><button type="submit" class="btn btn-primary btn-sm" onclick="#">&nbsp;&nbsp;回&nbsp;&nbsp;复&nbsp;&nbsp;</button></div></form></div></div></li><!-- 回复输入框 --><li class="pb-3 pt-3"><form method="post" th:action="@{|/comment/add/${post.id}|}"><div><input type="text" class="input-size" name="content" placeholder="请输入你的观点"/><input type="hidden" name="entityType" value="2"><input type="hidden" name="entityId" th:value="${cvo.comment.id}"></div><div class="text-right mt-2"><button type="submit" class="btn btn-primary btn-sm" onclick="#">&nbsp;&nbsp;回&nbsp;&nbsp;复&nbsp;&nbsp;</button></div></form></li></ul></div></li></ul><!-- 分页 --><nav class="mt-5" th:replace="index::pagination"><ul class="pagination justify-content-center"><li class="page-item"><a class="page-link" href="#">首页</a></li><li class="page-item disabled"><a class="page-link" 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