【Java Web】实现帖子点赞功能——基于Redis

  • 点赞
    • 支持对帖子、评论点赞;
    • 第一次点赞,第二次点赞取消;
  • 首页显示点赞数量
    • 统计帖子点赞数量;
  • 详情页显示点赞数量
    • 统计点赞数量;
    • 显示点赞状态;

1. LikeService定义一些关于点赞的操作

  • 点赞:
    • 如果已经点过赞,就取消点赞;
    • 如果没点过赞,就add到redis;
  • 查询某个实体点赞的数量 ;
  • 查询某人某实体的点赞状态;
package com.nowcoder.community.service;

import com.nowcoder.community.util.RedisKeyUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

@Service
public class LikeService {
    @Autowired
    private RedisTemplate redisTemplate;

    // 点赞
    public void like(int userId, int entityType, int entityId){
        String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType,entityId);
        boolean isMember = redisTemplate.opsForSet().isMember(entityLikeKey,userId);
        if(isMember){ // 已经点过赞
            redisTemplate.opsForSet().remove(entityLikeKey,userId);
        } else { // 没点过赞
            redisTemplate.opsForSet().add(entityLikeKey,userId);
        }
    }

    // 查询某个实体点赞的数量
    public long findEntityLikeCount(int entityType, int entityId){
        String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType,entityId);
        return redisTemplate.opsForSet().size(entityLikeKey);
    }

    // 查询某人某实体的点赞状态
    public int findEntityLikeStatus(int userId, int entityType, int entityId){
        String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType,entityId);
         return redisTemplate.opsForSet().isMember(entityLikeKey, userId) ? 1 : 0;
    }
}

2. 点赞将提交异步请求,将结果以JSON传给页面

package com.nowcoder.community.controller;

import com.nowcoder.community.annotation.LoginRequired;
import com.nowcoder.community.entity.User;
import com.nowcoder.community.service.LikeService;
import com.nowcoder.community.util.CommunityUtil;
import com.nowcoder.community.util.HostHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.HashMap;
import java.util.Map;

@Controller
public class LikeController {

    @Autowired
    private LikeService likeService;

    @Autowired
    private HostHolder hostHolder;

    @RequestMapping(path="/like",method = RequestMethod.POST)
    @ResponseBody
    public String like(int entityType, int entityId){
        // 当前用户
        User user = hostHolder.getUser();

        // 点赞
        likeService.like(user.getId(), entityType, entityId);

        // 返回点赞数量
        long likeCount = likeService.findEntityLikeCount(entityType, entityId);

        // 点赞状态
        int likeStatus = likeService.findEntityLikeStatus(user.getId(), entityType, entityId);

        // 封装传给页面
        Map<String,Object> map = new HashMap<>();
        map.put("likeCount",likeCount);
        map.put("likeStatus",likeStatus);

        return CommunityUtil.getJSONString(0, null, map);
    }
}

3. 帖子详情页面显示点赞信息

如果当前用户已经点赞,点赞处应当显示已赞

package com.nowcoder.community.controller;

import com.nowcoder.community.entity.Comment;
import com.nowcoder.community.entity.DiscussPost;
import com.nowcoder.community.entity.Page;
import com.nowcoder.community.entity.User;
import com.nowcoder.community.service.CommentService;
import com.nowcoder.community.service.DiscussPostService;
import com.nowcoder.community.service.LikeService;
import com.nowcoder.community.service.UserService;
import com.nowcoder.community.util.CommunityConstant;
import com.nowcoder.community.util.CommunityUtil;
import com.nowcoder.community.util.HostHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.*;

@Controller
@RequestMapping("/discuss")
public class DiscussPostController implements CommunityConstant {

    @Autowired
    private DiscussPostService discussPostService;

    @Autowired
    private HostHolder hostHolder;

    @Autowired
    private UserService userService;

    @Autowired
    private CommentService commentService;

    @Autowired
    private LikeService likeService;

    @RequestMapping(path = "/add", method = RequestMethod.POST)
    @ResponseBody
    public String addDiscussPost(String title, String content) {
        User user = hostHolder.getUser();
        if (user == null) {
            return CommunityUtil.getJSONString(403, "你还没有登录哦!");
        }

        DiscussPost post = new DiscussPost();
        post.setUserId(user.getId());
        post.setTitle(title);
        post.setContent(content);
        post.setCreateTime(new Date());
        discussPostService.addDiscussPost(post);

        // 报错的情况,将来统一处理.
        return CommunityUtil.getJSONString(0, "发布成功!");
    }

    @RequestMapping(path = "/detail/{discussPostId}", method = RequestMethod.GET)
    public String getDiscussPost(@PathVariable("discussPostId") int discussPostId, Model model, Page page) {
        // 帖子
        DiscussPost post = discussPostService.findDiscussPostById(discussPostId);
        model.addAttribute("post", post);
        // 作者
        User user = userService.findUserById(post.getUserId());
        model.addAttribute("user", user);

        // 点赞
        long likeCount = likeService.findEntityLikeCount(ENTITY_TYPE_POST, discussPostId);
        int likeStatus = hostHolder.getUser() == null ? 0 : likeService.findEntityLikeStatus(hostHolder.getUser().getId(), ENTITY_TYPE_POST, post.getId());
        model.addAttribute("likeCount",likeCount);
        model.addAttribute("likeStatus",likeStatus);


        // 评论分页信息
        page.setLimit(5);
        page.setPath("/discuss/detail/" + discussPostId);
        page.setRows(post.getCommentCount());

        // 评论: 给帖子的评论
        // 回复: 给评论的评论
        // 评论列表
        List<Comment> commentList = commentService.findCommentsByEntity(
                ENTITY_TYPE_POST, post.getId(), page.getOffset(), page.getLimit());
        // 评论VO列表
        List<Map<String, Object>> commentVoList = new ArrayList<>();
        if (commentList != null) {
            for (Comment comment : commentList) {
                // 评论VO
                Map<String, Object> commentVo = new HashMap<>();
                // 评论
                commentVo.put("comment", comment);
                // 作者
                commentVo.put("user", userService.findUserById(comment.getUserId()));

                // 点赞
                likeCount = likeService.findEntityLikeCount(ENTITY_TYPE_COMMENT, comment.getId());
                likeStatus = hostHolder.getUser() == null? 0 : likeService.findEntityLikeStatus(hostHolder.getUser().getId(), ENTITY_TYPE_COMMENT, comment.getId());
                commentVo.put("likeCount",likeCount);
                commentVo.put("likeStatus",likeStatus);

                // 回复列表
                List<Comment> replyList = commentService.findCommentsByEntity(
                        ENTITY_TYPE_COMMENT, comment.getId(), 0, Integer.MAX_VALUE);
                // 回复VO列表
                List<Map<String, Object>> replyVoList = new ArrayList<>();
                if (replyList != null) {
                    for (Comment reply : replyList) {
                        Map<String, Object> replyVo = new HashMap<>();
                        // 回复
                        replyVo.put("reply", reply);
                        // 作者
                        replyVo.put("user", userService.findUserById(reply.getUserId()));
                        // 回复目标
                        User target = reply.getTargetId() == 0 ? null : userService.findUserById(reply.getTargetId());
                        replyVo.put("target", target);

                        // 点赞
                        likeCount = likeService.findEntityLikeCount(ENTITY_TYPE_COMMENT, reply.getId());
                        likeStatus = hostHolder.getUser() == null? 0 : likeService.findEntityLikeStatus(hostHolder.getUser().getId(), ENTITY_TYPE_COMMENT, reply.getId());
                        replyVo.put("likeCount",likeCount);
                        replyVo.put("likeStatus",likeStatus);

                        replyVoList.add(replyVo);
                    }
                }
                commentVo.put("replys", replyVoList);

                // 回复数量
                int replyCount = commentService.findCommentCount(ENTITY_TYPE_COMMENT, comment.getId());
                commentVo.put("replyCount", replyCount);

                commentVoList.add(commentVo);
            }
        }

        model.addAttribute("comments", commentVoList);

        return "/site/discuss-detail";
    }

}

4. discuss-detail.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" th:href="@{/img/ucas.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">
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				</button>
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				<div class="collapse navbar-collapse" id="navbarSupportedContent">
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						<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>
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								<span class="dropdown-item text-center text-secondary">nowcoder</span>
							</div>
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					<!-- 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="javascript:;" th:onclick="|like(this,1,${post.id});|" class="text-primary">
									<b th:text="${likeStatus == 1 ? '已赞':'赞'}"></b> <i th:text="${likeCount}">11</i>
								</a>
							</li>
							<li class="d-inline ml-2">|</li>
							<li class="d-inline ml-2"><a href="#replyform" class="text-primary">回帖 <i th:text="${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;&nbsp;&nbsp;&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="javascript:;" class="text-primary" th:onclick="|like(this,2,${cvo.comment.id})|">
										<b th:text="${cvo.likeStatus==1?'已赞':'赞'}"></b>(<i th:text="${cvo.likeCount}">1</i>)
									</a>
								</li>
								<li class="d-inline ml-2">|</li>
								<li class="d-inline ml-2"><a href="#" class="text-primary">回复(<i th:text="${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="javascript:;" class="text-primary" th:onclick="|like(this,2,${rvo.reply.id})|">
												<b th:text="${rvo.likeStatus == 1?'已赞':'赞'}"></b>(<i th:text="${rvo.likeCount}">1</i>)
											</a>
										</li>
										<li class="d-inline ml-2">|</li>
										<li class="d-inline ml-2"><a th:href="|#huifu-${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;&nbsp;&nbsp;&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;&nbsp;&nbsp;&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" href="#">上一页</a></li>
					<li class="page-item active"><a class="page-link" href="#">1</a></li>
					<li class="page-item"><a class="page-link" href="#">2</a></li>
					<li class="page-item"><a class="page-link" href="#">3</a></li>
					<li class="page-item"><a class="page-link" href="#">4</a></li>
					<li class="page-item"><a class="page-link" href="#">5</a></li>
					<li class="page-item"><a class="page-link" href="#">下一页</a></li>
					<li class="page-item"><a class="page-link" href="#">末页</a></li>
				</ul>
			</nav>
		</div>
		<!-- 回帖输入 -->
		<div class="container mt-3">
			<form class="replyform" method="post" th:action="@{|/comment/add/${post.id}|}">
				<p class="mt-3">
					<a name="replyform"></a>
					<textarea placeholder="在这里畅所欲言你的看法吧!" name="content"></textarea>
					<input type="hidden" name="entityType" value="1">
					<input type="hidden" name="entityId" th:value="${post.id}">
				</p>
				<p class="text-right">
					<button type="submit" class="btn btn-primary btn-sm">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</button>
				</p>
			</form>
		</div>
	</div>

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<script src="https://code.jquery.com/jquery-3.3.1.min.js" crossorigin="anonymous"></script>
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<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" crossorigin="anonymous"></script>
<script th:src="@{/js/global.js}"></script>
<script th:src="@{/js/discuss.js}"></script>
</body>
</html>

5. discuss.js

function like(btn, entityType, entityId){
    $.post(
        CONTEXT_PATH + "/like",
        {"entityType":entityType, "entityId":entityId},
        function (data) {
            data = $.parseJSON(data);
            if(data.code == 0){
                $(btn).children("i").text(data.likeCount);
                $(btn).children("b").text(data.likeStatus = 1 ? '已赞' : '赞');
            } else {
                alert(data.msg);
            }
        }
    )
}

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