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CREATE TABLE `sb_like` ( `id` bigint(20) NOT NULL, `item_id` bigint(20) NOT NULL COMMENT '点赞条目id', `user_id` bigint(20) NOT NULL COMMENT '用户id', `like` tinyint(1) NOT NULL COMMENT '是否点赞，true点赞，false未点赞', `create_time` datetime DEFAULT NULL, `update_time` datetime DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `un` (`item_id`,`user_id`), KEY `k` (`item_id`,`user_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_german2_ci

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ä1/2ç1/2®ï1/4cn.j3code.community.api.v1.controller

java复制代码@Slf4j
@ResponseResult
@AllArgsConstructor
@RestController
@RequestMapping(UrlPrefixConstants.WEB_V1 + "/like")
public class LikeController {

    private final LikeService likeService;

    /**
     * 点赞
     * @param request
     */
    @PostMapping("/")
    public void like(@Validated @RequestBody LikeRequest request) {
        likeService.like(request);
    }
}

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ä1/2ç1/2®ï1/4cn.j3code.community.api.v1.request

java复制代码@Data
public class LikeRequest {
    @NotNull(message = "条目id不为空")
    private Long itemId;
    @NotNull(message = "点赞不为空")
    private Boolean like;
    @NotNull(message = "类型不为空")
    private CommentTypeEnum type;
}

CommentTypeEnum æä ̧3/4

ä1/2ç1/2®ï1/4cn.j3code.config.enums

java复制代码@Getter
public enum CommentTypeEnum {
    COMMODITY(1, "商品评论"),

    POST_COMMENT(2, "帖子评论"),

    POST(3, "帖子"),
    ;

    @EnumValue
    private Integer value;

    private String description;

    CommentTypeEnum(Integer value, String description) {
        this.value = value;
        this.description = description;
    }
}

2ï1/4service

ä1/2ç1/2®ï1/4cn.j3code.community.service

java复制代码public interface LikeService extends IService<Like> {
    void like(LikeRequest request);
}
@Slf4j
@AllArgsConstructor
@Service
public class LikeServiceImpl extends ServiceImpl<LikeMapper, Like>
    implements LikeService {

    private final RedisTemplate<String, Object> redisTemplate;

    @Override
    public void like(LikeRequest request) {
        redisTemplate.opsForHash().put(
            SbUtil.getItemLikeKey(request.getType().getValue() + ":" + request.getItemId()),
            Objects.requireNonNull(SecurityUtil.getUserId(), "获取登录人信息出错！").toString(),
            request.getLike());
    }
}

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ä1/2ç1/2®ï1/4cn.j3code.community.schedule

java复制代码@Slf4j
@Component
@AllArgsConstructor
public class PostLikeSchedule {

    private final PostService postService;

    /**
     * 同步帖子点赞
     */
    @DistributedLock
    @Scheduled(cron = "11 0/9 * * * ?")
    public void syncPostLike(){
        postService.syncPostLike();
    }
}

2ï1/4service

ä1/2ç1/2®ï1/4cn.j3code.community.service

java复制代码public interface PostService extends IService<Post> {
    void syncPostLike();
}
@Slf4j
@AllArgsConstructor
@Service
public class PostServiceImpl extends ServiceImpl<PostMapper, Post>
    implements PostService {
    
    private final LikeServiceImpl likeService;
    private final RedisTemplate<String, Object> redisTemplate;
    private final TransactionTemplate transactionTemplate;

    @Override
    public void syncPostLike() {
        // 获取帖子点赞 key
        List<String> keys = new ArrayList<>(redisTemplate.keys(SbUtil.getItemLikeKey(CommentTypeEnum.POST.getValue() + ":*")));
        if (CollectionUtils.isEmpty(keys)) {
            return;
        }

        Set<Long> commentIdList = keys.stream().map(key -> Long.valueOf(key.substring(key.lastIndexOf(":") + 1)))
            .collect(Collectors.toSet());

        // 批量查看 redis 评论id，的点赞数据
        ItemLikeBO itemLikeBO = likeService.getItemLikeCount(new ArrayList<>(commentIdList), CommentTypeEnum.POST, Boolean.TRUE);
        Map<Long, Integer> itemLikeCount = itemLikeBO.getItemLikeCount();

        /**
         * 帖子id 对应，用户id 和 点赞状态 的 map
         */
        Map<Long, Map<Long, Boolean>> postToUserLikeMap = itemLikeBO.getItemIdToUserLikeMap();

        // 待修改的评论的点赞数量集合
        List<Post> updatePostList = new ArrayList<>();
        // 待插入的点赞集合
        List<Like> saveLikeList = new ArrayList<>();

        postToUserLikeMap.forEach((postId, likeMap) -> {
            Post post = new Post();
            post.setId(postId);
            post.setLikeCount(itemLikeCount.get(postId));
            updatePostList.add(post);

            likeMap.forEach((key, value) -> {
                Like like = new Like();
                like.setId(SnowFlakeUtil.getId());
                like.setItemId(postId);
                like.setUserId(key);
                like.setLike(value);
                like.setCreateTime(LocalDateTime.now());
                like.setUpdateTime(LocalDateTime.now());
                saveLikeList.add(like);
            });
        });

        Map<Long, Post> postMap = lambdaQuery()
            .in(Post::getId, postToUserLikeMap.keySet()).list()
            .stream().collect(Collectors.toMap(Post::getId, item -> item));
        // 点赞数量等于 数据库 + redis
        updatePostList.forEach(item ->
                               item.setLikeCount(item.getLikeCount() + postMap.get(item.getId()).getLikeCount()));

        String format = LocalDateTime.now().format(DateTimeFormatter.ISO_LOCAL_DATE_TIME);
        log.info(format + "-同步点赞数据：updatePostList={}，saveLikeList={}",
                 JSON.toJSONString(updatePostList),
                 JSON.toJSONString(saveLikeList));

        // 修改数据库
        MyTransactionTemplate.execute(transactionTemplate, accept -> {
            CollUtil.split(updatePostList, 100).forEach(this::updateBatchById);
            CollUtil.split(saveLikeList, 100).forEach(likeService::saveOrUpdateByDuplicate);
        }, format + "-同步帖子点赞逻辑出错！");
    }
}

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ä1/2ç1/2®ï1/4cn.j3code.community.service

java复制代码public interface LikeService extends IService<Like> {
    /**
     *
     * @param itemIdList 条目id集合
     * @param type 条目的数据类型
     * @param redisDataRemove 统计完后，是否移除redis中的数据
     * @return
     */
    ItemLikeBO getItemLikeCount(List<Long> itemIdList, CommentTypeEnum type, Boolean redisDataRemove);
}
@Slf4j
@AllArgsConstructor
@Service
public class LikeServiceImpl extends ServiceImpl<LikeMapper, Like>
    implements LikeService {

    private final RedisTemplate<String, Object> redisTemplate;

    @Override
    public ItemLikeBO getItemLikeCount(List<Long> itemIdList, CommentTypeEnum type, Boolean redisDataRemove) {
        ItemLikeBO itemLikeBO = new ItemLikeBO();
        Map<Long, Integer> result = new HashMap<>();
        itemIdList.forEach(itemId -> result.put(itemId, 0));

        // 批量查看 redis 评论id，的点赞数据
        List<Object> executePipelined = redisTemplate.executePipelined(new SessionCallback<>() {
            @Override
            public <K, V> Object execute(RedisOperations<K, V> redisOperations) throws DataAccessException {
                for (Long itemId : itemIdList) {
                    redisOperations.opsForHash().entries((K) SbUtil.getItemLikeKey(type.getValue() + ":" + itemId));
                }
                return null;
            }
        });

        /**
         * 评论id 对应，用户id 和 点赞状态 的 map
         */
        Map<Long, Map<Long, Boolean>> commentToUserLikeMap = new HashMap<>();
        for (int i = 0; i < itemIdList.size(); i++) {
            if (Objects.isNull(executePipelined.get(i))) {
                continue;
            }
            Long commentId = itemIdList.get(i);
            Map<String, Boolean> likeMap = (Map<String, Boolean>) executePipelined.get(i);

            Map<Long, Boolean> lb = new HashMap<>();
            likeMap.forEach((k, v) -> lb.put(Long.valueOf(k), v));

            commentToUserLikeMap.put(commentId, lb);


            if (redisDataRemove) {
                /**
                 * 这里会有一点点问题，就是如果在获取点赞 与 删除点赞 的时间空隙之间，同一个用户又操作了同一个评论的点赞
                 * 那这将会导致数据丢失
                 * 解决方法：
                 * 1、加锁
                 * 2、改用 MQ 方式
                 */
                // 删除一下 redis 中的 点赞 记录
                redisTemplate.opsForHash().delete(
                    SbUtil.getItemLikeKey(type.getValue() + ":" + commentId),
                    likeMap.keySet().stream().map(Object::toString).toArray(Object[]::new));
            }
        }

        for (int i = 0; i < itemIdList.size(); i++) {
            Map<Long, Boolean> redisUserLikeMap = commentToUserLikeMap.get(itemIdList.get(i));
            if (Objects.nonNull(redisUserLikeMap) && CollectionUtils.isNotEmpty(redisUserLikeMap.keySet())) {
                // 查询数据库中，该评论的点赞记录
                Map<Long, Boolean> dbUserLikeMap = lambdaQuery()
                    .eq(Like::getItemId, itemIdList.get(i))
                    .eq(Like::getLike, Boolean.TRUE)
                    .in(Like::getUserId, redisUserLikeMap.keySet())
                    .list().stream().collect(Collectors.toMap(Like::getUserId, Like::getLike));
                // redis 与 数据库点赞记录 结合
                AtomicInteger redisLikeCount = new AtomicInteger(0);
                for (Map.Entry<Long, Boolean> entry : redisUserLikeMap.entrySet()) {
                    // 数据库存在点赞，redis 取消点赞，那点赞数量减一
                    if (dbUserLikeMap.containsKey(entry.getKey()) && Boolean.FALSE.equals(entry.getValue())) {
                        redisLikeCount.set(redisLikeCount.get() - 1);
                    }
                    // 数据库存在点赞，redis 存在点赞，那 Redis 点赞状态变为 false，不记录总点赞数量中
                    if (dbUserLikeMap.containsKey(entry.getKey()) && Boolean.TRUE.equals(entry.getValue())) {
                        entry.setValue(Boolean.FALSE);
                    }
                }

                redisLikeCount.set(redisLikeCount.get() +
                                   Integer.parseInt(redisUserLikeMap.values().stream().filter(like -> like).count() + "")
                                  );
                result.put(itemIdList.get(i), redisLikeCount.get());
            }
        }

        itemLikeBO.setItemLikeCount(result);
        itemLikeBO.setItemIdToUserLikeMap(commentToUserLikeMap);
        return itemLikeBO;
    }
}

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java复制代码public IPage<PostVO> page(PostPageRequest request) {

    // 先查询 MySQL 的业务数据

    // 用户评论点赞状态
    Map<Long, Boolean> itemIdToLikeMap = likeService.getItemLikeState(voiPage.getRecords().stream().map(PostVO::getId).collect(Collectors.toList()), CommentTypeEnum.POST);
    // redis 中评论点赞数量
    Map<Long, Integer> itemIdToLikeCountMap = likeService.getItemLikeCount(voiPage.getRecords().stream().map(PostVO::getId).collect(Collectors.toList()), CommentTypeEnum.POST, Boolean.FALSE)
        .getItemLikeCount();

    // 填充评论点赞数量及当前用户点赞状态，用户信息
    业务数据列表.forEach(postVO -> {
        设置业务数据点赞数据(业务MySQL点赞数量 + itemIdToLikeCountMap.get(postVO.getId()));
        设置业务数据用户点赞状态(itemIdToLikeMap.get(postVO.getId()));
    });

}

getItemLikeState æ¹æ³å®ç°ï1/4

java复制代码public Map<Long, Boolean> getItemLikeState(List<Long> itemIdList, CommentTypeEnum type) {
    Map<Long, Boolean> result = new HashMap<>();
    itemIdList.forEach(itemId -> result.put(itemId, Boolean.FALSE));

    if (Objects.isNull(SecurityUtil.getUserId())) {
        // 未登录
        return result;
    }

    if (CollectionUtils.isEmpty(itemIdList)) {
        return result;
    }

    // 查看数据库中是否有用户点赞记录
    lambdaQuery()
        .eq(Like::getUserId, SecurityUtil.getUserId())
        .eq(Like::getLike, Boolean.TRUE)
        .in(Like::getItemId, itemIdList)
        .list().forEach(likeObj -> {
        if (likeObj.getLike()) {
            result.put(likeObj.getItemId(), Boolean.TRUE);
        }
    });

    // 查看 redis 用户点赞记录
    List<Object> executePipelined = redisTemplate.executePipelined(new SessionCallback<>() {
        @Override
        public <K, V> Object execute(RedisOperations<K, V> redisOperations) throws DataAccessException {
            for (Long itemId : itemIdList) {
                redisOperations.opsForHash().get(
                    (K) SbUtil.getItemLikeKey(type.getValue() + ":" + itemId),
                    SecurityUtil.getUserId().toString());
            }
            return null;
        }
    });

    for (int i = 0; i < itemIdList.size(); i++) {
        if (Objects.nonNull(executePipelined.get(i))) {
            result.put(itemIdList.get(i), (Boolean) executePipelined.get(i));
        }
    }

    return result;
}

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