问答平台（4），收到的赞

重构点赞功能

- 以用户为key，记录点赞数量
- increment(key)、decrement(key)

开发个人主页

- 以用户为key，查询点赞数量

工具类

• RedisKeyUtil：增加内容

  private static final String PREFIX_USER_LIKE = "like:user";
  // 某个用户的赞
  // like:user:userId -> int
  public static String getUserLikeKey(int userId) {
      return PREFIX_USER_LIKE + SPLIT + userId;
  }

业务层

• LikeService：重构，添加一个参数(entityUserId)

  // 点赞
  public void like(int userId, int entityType, int entityId, int entityUserId) {
      redisTemplate.execute(new SessionCallback() {
          @Override
          public Object execute(RedisOperations operations) throws DataAccessException {
              String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType, entityId);
              // 添加
              String userLikeKey = RedisKeyUtil.getUserLikeKey(entityUserId);
  
              boolean isMember = operations.opsForSet().isMember(entityLikeKey, userId);
  
              // 开启事务
              operations.multi();
  
              if (isMember) {
                  operations.opsForSet().remove(entityLikeKey, userId);
                  operations.opsForValue().decrement(userLikeKey);
              } else {
                  operations.opsForSet().add(entityLikeKey, userId);
                  operations.opsForValue().increment(userLikeKey);
              }
  
              return operations.exec();
          }
      });
  }
  
  // 查询某个用户获得的赞
  public int findUserLikeCount(int userId) {
      String userLikeKey = RedisKeyUtil.getUserLikeKey(userId);
      Integer count = (Integer) redisTemplate.opsForValue().get(userLikeKey);
      return count == null ? 0 : count.intValue();
  }

表现层

• LikeController：重构，添加一个参数(entityUserId)

  @RequestMapping(path = "/like", method = RequestMethod.POST)
  @ResponseBody
  public String like(int entityType, int entityId, int entityUserId) {
      User user = hostHolder.getUser();
  
      // 点赞
      likeService.like(user.getId(), entityType, entityId, entityUserId);
      // 数量
      long likeCount = likeService.findEntityLikeCount(entityType, entityId);
      // 状态
      int likeStatus = likeService.findEntityLikeStatus(user.getId(), entityType, entityId);
      // 返回的结果
      Map<String, Object> map = new HashMap<>();
      map.put("likeCount", likeCount);
      map.put("likeStatus", likeStatus);
  
      return CommunityUtil.getJSONString(0, null, map);
  }

• UserController：新增方法

  // 个人主页
  @RequestMapping(path = "/profile/{userId}", method = RequestMethod.GET)
  public String getProfilePage(@PathVariable("userId") int userId, Model model) {
      User user = userService.findUserById(userId);
      if (user == null) {
          throw new RuntimeException("该用户不存在!");
      }
  
      // 用户
      model.addAttribute("user", user);
      // 点赞数量
      int likeCount = likeService.findUserLikeCount(userId);
      model.addAttribute("likeCount", likeCount);
  
      return "/site/profile";
  }

页面

• discuss-detail.html

  <!-- 内容 -->
  <!-- 作者 -->
  <li class="d-inline ml-2">
      <a href="javascript:;" th:onclick="|like(this,1,${post.id},${post.userId});|" class="text-primary">
          <b th:text="${likeStatus==1?'已赞':'赞'}">赞</b> <i th:text="${likeCount}">11</i>
      </a>
  </li>
  <!-- 回帖列表 -->
  <li class="d-inline ml-2">
      <a href="javascript:;" th:onclick="|like(this,2,${cvo.comment.id},${cvo.comment.userId});|" class="text-primary">
          <b th:text="${cvo.likeStatus==1?'已赞':'赞'}">赞</b> (<i th:text="${cvo.likeCount}">1</i>)
      </a>
  </li>
  <!-- 回复列表 -->
  <li class="d-inline ml-2">
      <a href="javascript:;" th:onclick="|like(this,2,${rvo.reply.id},${rvo.reply.userId});|" class="text-primary">
          <b th:text="${rvo.likeStatus==1?'已赞':'赞'}">赞</b> (<i th:text="${rvo.likeCount}">1</i>)
      </a>
  </li>

• discuss.js：重构，添加一个参数(entityUserId)

  function like(btn, entityType, entityId, entityUserId) {
      $.post(
          CONTEXT_PATH + "/like",
          {"entityType": entityType, "entityId": entityId, "entityUserId": entityUserId},
          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);
              }
          }
      );
  }

• index.html

  <!-- 头部 -->
  <!-- 功能 -->
  <a class="dropdown-item text-center" 
  th:href="@{|/user/profile/${loginUser.id}|}">个人主页</a>
  <!-- 帖子列表 -->
  <a th:href="@{|/user/profile/${map.user.id}|}">
      <img th:src="${map.user.headerUrl}" class="mr-4 rounded-circle" alt="用户头像" style="width:50px;height:50px;">
  </a>

• profile.html

  <!-- 内容 -->
  <!-- 个人信息 -->
  <img th:src="${user.headerUrl}" class="align-self-start mr-4 rounded-circle" alt="用户头像" style="width:50px;">
  <span th:utext="${user.username}">nowcoder</span>
  <span>注册于 <i class="text-muted" th:text="${#dates.format(user.createTime, 'yyyy-MM-dd HH:mm:ss')}">2015-06-12 15:20:12</i></span>
  <span class="ml-4">获得了 <i class="text-danger" th:text="${likeCount}">87</i> 个赞</span>