4.4 我收到的赞

 在用户点赞的是时候，增加一个维度。

在RedisKeyUtil中添加

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

LikeService

涉及到了多个操作，使用事务，另外，查询要放到事务之外，如果放到事务之内，不会立马就返回查询结果。

    //点赞entityUserId：实体作者id
    public void like(int userId, int entityType, int entityId, int entityUserId){
        redisTemplate.execute(new SessionCallback() {
            @Override
            public Object execute(RedisOperations operations) throws DataAccessException {
                //先拼好两个key
                String entityLikeKey = RedisKeyUtil.getEntityLikeKey(entityType, entityId);
                String userLikeKey = RedisKeyUtil.getUserLikeKey(entityUserId);
                //判断某个用户是否对某个实体点过赞
                boolean isMember = operations.opsForSet().isMember(entityLikeKey,userId);
                operations.multi();//开启事务
                if(isMember){
                    operations.opsForSet().remove(entityLikeKey, userId);
                    operations.opsForValue().decrement(userLikeKey);
                }
                else{
                    operations.opsForSet().add(entityLikeKey, userId);
                    if(operations.opsForValue().get(userLikeKey) == null){
                        operations.opsForValue().set(userLikeKey, 0);
                    }
                    operations.opsForValue().increment(userLikeKey);
                }
                return operations.exec();//表示的是提交事务
            }
        });
    }

额外添加一个查询某个用户获得的赞的数量的方法

    public int findUserLikeCount(int userId){
        String userLikeKey = RedisKeyUtil.getUserLikeKey(userId);
        Integer count = (Integer) redisTemplate.opsForValue().get(userLikeKey);
        return count == null ? 0: count.intValue();
    }

LikeController

需要额外添加 一个entityUserId参数

@RequestMapping(path="/like",method = RequestMethod.POST)
@ResponseBody
public String like(int entityType, int entityId, int entityUserId){
    //当前用户点赞
    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

显示个人主页时需要把用户收到的赞的总数量放到Model之中去。

    @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";
    }