问答平台（6），社区搜索功能

搜索服务

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- 将帖子保存至 Elasticsearch 服务器。
- 从 Elasticsearch 服务器删除帖子。
- 从 Elasticsearch 服务器搜索帖子。

发布事件

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- 发布帖子时，将帖子异步地提交到 Elasticsearch 服务器。
- 增加评论时，将帖子异步地提交到 Elasticsearch 服务器。
- 在消费事件中增加一个方法，消费帖子发布事件。（发帖或更改事件存到 Kafka消息队列中，消费事件并将帖子存到 es服务器中）

显示结果

社区搜索功能-图示

  • 在控制器中处理搜索请求，在 HTML 上显示搜索结果。

业务层

  • ElasticsearchService: 新增
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    @Service
    public class ElasticsearchService {

        @Autowired
        private DiscussPostRepository discussepository;

        @Autowired
        private ElasticsearchTemplate elasticTemplate;

        public void saveDiscussPost(DiscussPost post) {
            discussepository.save(post);
        }

        public void deleteDiscussPost(int id) {
            discussepository.deleteById(id);
        }

        public Page<DiscussPost> searchDiscussPost(String keyword, int current, int limit) {
            SearchQuery searchQuery = new NativeSearchQueryBuilder()
                    .withQuery(QueryBuilders.multiMatchQuery(keyword, "title", "content"))
                    .withSort(SortBuilders.fieldSort("type").order(SortOrder.DESC))
                    .withSort(SortBuilders.fieldSort("score").order(SortOrder.DESC))
                    .withSort(SortBuilders.fieldSort("createTime").order(SortOrder.DESC))
                    .withPageable(PageRequest.of(current, limit))
                    .withHighlightFields(
                            new HighlightBuilder.Field("title").preTags("<em>").postTags("</em>"),
                            new HighlightBuilder.Field("content").preTags("<em>").postTags("</em>")
                    ).build();

            return elasticTemplate.queryForPage(searchQuery, DiscussPost.class, new SearchResultMapper() {
                @Override
                public <T> AggregatedPage<T> mapResults(SearchResponse response, Class<T> aClass, Pageable pageable) {
                    SearchHits hits = response.getHits();
                    if (hits.getTotalHits() <= 0) {
                        return null;
                    }

                    List<DiscussPost> list = new ArrayList<>();
                    for (SearchHit hit : hits) {
                        DiscussPost post = new DiscussPost();

                        String id = hit.getSourceAsMap().get("id").toString();
                        post.setId(Integer.valueOf(id));

                        String userId = hit.getSourceAsMap().get("userId").toString();
                        post.setUserId(Integer.valueOf(userId));

                        String title = hit.getSourceAsMap().get("title").toString();
                        post.setTitle(title);

                        String content = hit.getSourceAsMap().get("content").toString();
                        post.setContent(content);

                        String status = hit.getSourceAsMap().get("status").toString();
                        post.setStatus(Integer.valueOf(status));

                        String createTime = hit.getSourceAsMap().get("createTime").toString();
                        post.setCreateTime(new Date(Long.valueOf(createTime)));

                        String commentCount = hit.getSourceAsMap().get("commentCount").toString();
                        post.setCommentCount(Integer.valueOf(commentCount));

                        // 处理高亮显示的结果
                        HighlightField titleField = hit.getHighlightFields().get("title");
                        if (titleField != null) {
                            post.setTitle(titleField.getFragments()[0].toString());
                        }

                        HighlightField contentField = hit.getHighlightFields().get("content");
                        if (contentField != null) {
                            post.setContent(contentField.getFragments()[0].toString());
                        }

                        list.add(post);
                    }

                    return new AggregatedPageImpl(list, pageable,
                            hits.getTotalHits(), response.getAggregations(), response.getScrollId(), hits.getMaxScore());
                }
            });
        }
    }

表现层

  • DiscussPostController: 修改
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    @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, "还没有登录!");
        }

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

        // 触发发帖事件
        Event event = new Event()
                .setTopic(TOPIC_PUBLISH)
                .setUserId(user.getId())
                .setEntityType(ENTITY_TYPE_POST)
                .setEntityId(post.getId());
        eventProducer.fireEvent(event);

        // 计算帖子分数
        // String redisKey = RedisKeyUtil.getPostScoreKey();
        // redisTemplate.opsForSet().add(redisKey, post.getId());

        // 报错的情况，将来统一处理
        return CommunityUtil.getJSONString(0, "发布成功!");
    }
  • CommentController: 修改
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    @RequestMapping(path = "/add/{discussPostId}", method = RequestMethod.POST)
    public String addComment(@PathVariable("discussPostId") int discussPostId, Comment comment) {
        comment.setUserId(hostHolder.getUser().getId());
        comment.setStatus(0);
        comment.setCreateTime(new Date());
        commentService.addComment(comment);

        // 触发评论事件
        Event event = new Event()
                .setTopic(TOPIC_COMMENT)
                .setUserId(hostHolder.getUser().getId())
                .setEntityType(comment.getEntityType())
                .setEntityId(comment.getEntityId())
                .setData("postId", discussPostId);
        if (comment.getEntityType() == ENTITY_TYPE_POST) {
            DiscussPost target = discussPostService.findDiscussPostById(comment.getEntityId());
            event.setEntityUserId(target.getUserId());
        } else if (comment.getEntityType() == ENTITY_TYPE_COMMENT) {
            Comment target = commentService.findCommentById(comment.getEntityId());
            event.setEntityUserId(target.getUserId());
        }
        eventProducer.fireEvent(event);

        if (comment.getEntityType() == ENTITY_TYPE_POST) {
            // 触发发帖事件
            event = new Event()
                    .setTopic(TOPIC_PUBLISH)
                    .setUserId(comment.getUserId())
                    .setEntityType(ENTITY_TYPE_POST)
                    .setEntityId(discussPostId);
            eventProducer.fireEvent(event);

            // 计算帖子分数
            // String redisKey = RedisKeyUtil.getPostScoreKey();
            // redisTemplate.opsForSet().add(redisKey, discussPostId);
        }

        return "redirect:/discuss/detail/" + discussPostId;
    }
  • SearchController: 新增
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    @Controller
    public class SearchController implements CommunityConstant {

        @Autowired
        private ElasticsearchService elasticsearchService;

        @Autowired
        private UserService userService;

        @Autowired
        private LikeService likeService;

        // search?keyword=xxx
        @RequestMapping(path = "/search", method = RequestMethod.GET)
        public String search(String keyword, Page page, Model model) {
            // 搜索帖子
            org.springframework.data.domain.Page<DiscussPost> searchResult =
                    elasticsearchService.searchDiscussPost(keyword, page.getCurrent() - 1, page.getLimit());
            // 聚合数据
            List<Map<String, Object>> discussPosts = new ArrayList<>();
            if (searchResult != null) {
                for (DiscussPost post : searchResult) {
                    Map<String, Object> map = new HashMap<>();
                    // 帖子
                    map.put("post", post);
                    // 作者
                    map.put("user", userService.findUserById(post.getUserId()));
                    // 点赞数量
                    map.put("likeCount", likeService.findEntityLikeCount(ENTITY_TYPE_POST, post.getId()));

                    discussPosts.add(map);
                }
            }
            model.addAttribute("discussPosts", discussPosts);
            model.addAttribute("keyword", keyword);

            // 分页信息
            page.setPath("/search?keyword=" + keyword);
            page.setRows(searchResult == null ? 0 : (int) searchResult.getTotalElements());

            return "/site/search";
        }
    }

发布事件

  • EventConsumer: 修改
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    // 消费发帖事件
    @KafkaListener(topics = {TOPIC_PUBLISH})
    public void handlePublishMessage(ConsumerRecord record) {
        if (record == null || record.value() == null) {
            logger.error("消息的内容为空!");
            return;
        }

        Event event = JSONObject.parseObject(record.value().toString(), Event.class);
        if (event == null) {
            logger.error("消息格式错误!");
            return;
        }

        DiscussPost post = discussPostService.findDiscussPostById(event.getEntityId());
        elasticsearchService.saveDiscussPost(post);
    }

页面

  • index.html: 修改
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    <!-- 头部：复用 -->
    <!-- 搜索 -->
  • search.html: 修改
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    <!-- 内容 -->
    <!-- 帖子列表 -->
    <!-- 分页 -->

结果展示

搜索结果-图示

#问答平台
问答平台（6），社区搜索功能
https://lcf163.github.io/2020/06/08/问答平台（6），社区搜索功能/
作者
乘风的小站
发布于
2020年6月8日
许可协议