【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
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<link rel="stylesheet" th:href="@{/css/global.css}" />
<link rel="stylesheet" th:href="@{/css/discuss-detail.css}" />
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<h6 class="mb-4">
<img src="http://static.nowcoder.com/images/img/icons/ico-discuss.png"/>
<span th:utext="${post.title}">备战春招，面试刷题跟他复习，一个月全搞定！</span>
<div class="float-right">
<button type="button" class="btn btn-danger btn-sm">置顶</button>
<button type="button" class="btn btn-danger btn-sm">加精</button>
<button type="button" class="btn btn-danger btn-sm">删除</button>
</div>
</h6>
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<a href="profile.html">
<img th:src="${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'}">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"> 回 帖 </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'}">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="${rvo.user.username}">寒江雪</b>:
</span>
<span th:if="${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>:
</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'}">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="${rvo.user.id}">
</div>
<div class="text-right mt-2">
<button type="submit" class="btn btn-primary btn-sm" onclick="#"> 回 复 </button>
</div>
</form>
</div>
</div>
</li>
<!-- 回复输入框 -->
<li class="pb-3 pt-3">
<form method="post" th:action="@{|/comment/add/${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="${cvo.comment.id}">
</div>
<div class="text-right mt-2">
<button type="submit" class="btn btn-primary btn-sm" onclick="#"> 回 复 </button>
</div>
</form>
</li>
</ul>
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</li>
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<form class="replyform" method="post" th:action="@{|/comment/add/${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>
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<button type="submit" class="btn btn-primary btn-sm"> 回 帖 </button>
</p>
</form>
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<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);
}
}
)
}