第6章 Elasticsearch，分布式搜索引擎【仿牛客网社区论坛项目】

第6章 Elasticsearch，分布式搜索引擎【仿牛客网社区论坛项目】

• 前言
• 推荐
• 项目总结
• 第6章 Elasticsearch，分布式搜索引擎

• 1.Elasticsearch入门
• 2.Spring整合Elasticsearch

• DiscussPostRepository
• DiscussPostController
• EventConsumer

• 3.开发社区搜索功能

• 最后

前言

2023-4-30 20:42:51

推荐

仿牛客网项目【面试】

项目总结

第6章 Elasticsearch，分布式搜索引擎

1.Elasticsearch入门

2.Spring整合Elasticsearch

导入依赖

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
        </dependency>

DiscussPostRepository

package com.jsss.community.dao.elasticsearch;

import com.jsss.community.entity.DiscussPost;
import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;
import org.springframework.stereotype.Repository;

/*
ElasticsearchRepository<DiscussPost, Integer>
DiscussPost：接口要处理的实体类
Integer：实体类中的主键是什么类型
ElasticsearchRepository：父接口，其中已经事先定义好了对es服务器访问的增删改查各种方法。Spring会给它自动做一个实现，我们直接去调就可以了。
 */
@Repository
public interface DiscussPostRepository extends ElasticsearchRepository<DiscussPost, Integer> {

}

DiscussPostController

发帖|删帖的时候，放到kakfa中了

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

       //触发发帖实践
        Event event =new Event()
                .setTopic(TOPIC_PUBLISH)
                .setUserId(user.getId())
                .setEntityType(ENTITY_TYPE_POST)
                .setEntityId(post.getId());

        eventProducer.fireEvent(event);

        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！");

   }

    // 删除
    @RequestMapping(path = "/delete", method = RequestMethod.POST)
    @ResponseBody
    public String setDelete(int id) {
        discussPostService.updateStatus(id, 2);

        // 触发删帖事件
        Event event = new Event()
                .setTopic(TOPIC_DELETE)
                .setUserId(hostHolder.getUser().getId())
                .setEntityType(ENTITY_TYPE_POST)
                .setEntityId(id);
        eventProducer.fireEvent(event);

        return CommunityUtil.getJSONString(0);
    }

EventConsumer

// 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);
    }

    // 消费删帖事件
    @KafkaListener(topics = {TOPIC_DELETE})
    public void handleDeleteMessage(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;
        }

        elasticsearchService.deleteDiscussPost(event.getEntityId());
    }

3.开发社区搜索功能

ElasticsearchService

public List<DiscussPost> searchDiscussPost(String keyword, int current, int limit) throws IOException {
        SearchRequest searchRequest = new SearchRequest("discusspost");//discusspost是索引名，就是表名

        NativeSearchQueryBuilder nativeSearchQueryBuilder = new NativeSearchQueryBuilder();

        //高亮
        HighlightBuilder highlightBuilder = new HighlightBuilder();
        highlightBuilder.field("title");
        highlightBuilder.field("content");
        highlightBuilder.requireFieldMatch(false);
        highlightBuilder.preTags("<em>");
        highlightBuilder.postTags("</em>");

        //构建搜索条件
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder()
                .query(QueryBuilders.multiMatchQuery(keyword, "title", "content"))
                .sort(SortBuilders.fieldSort("type").order(SortOrder.DESC))
                .sort(SortBuilders.fieldSort("score").order(SortOrder.DESC))
                .sort(SortBuilders.fieldSort("createTime").order(SortOrder.DESC))
                .from(current)// 指定从哪条开始查询
                .size(limit)// 需要查出的总记录条数
                .highlighter(highlightBuilder);//高亮

        searchRequest.source(searchSourceBuilder);
        //这有个异常
        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

        List<DiscussPost> list = new LinkedList<>();
        for (SearchHit hit : searchResponse.getHits().getHits()) {
            DiscussPost discussPost = JSONObject.parseObject(hit.getSourceAsString(), DiscussPost.class);

            // 处理高亮显示的结果
            HighlightField titleField = hit.getHighlightFields().get("title");
            if (titleField != null) {
                discussPost.setTitle(titleField.getFragments()[0].toString());
            }
            HighlightField contentField = hit.getHighlightFields().get("content");
            if (contentField != null) {
                discussPost.setContent(contentField.getFragments()[0].toString());
            }
//            System.out.println(discussPost);
            list.add(discussPost);
        }

        return list;
    }

最后

2023-7-31 20:34:10

这篇博客能写好的原因是：站在巨人的肩膀上

这篇博客要写好的目的是：做别人的肩膀

开源：为爱发电

学习：为我而行