Elasticsearch

概述

ElasticSearch(简称为es)是一个开源的高扩展的分布式全文检索引擎，它可以近乎 实时存储、检索数据；

本身扩展性很好，可以扩展到上百台服务器，处理PB级别（大数据时代）的数据。es是使用java开发并使用Lucene作为其核心来实现所有索引和搜索的功能，但是它的目的是通过简单的REST-ful的API来隐藏Lucene的复杂性，从而让全文搜索变得简单。

下载地址

ElasticSearch Kibana 安装 https://www.elastic.co/cn

es可视化界面：head的插件 https://github.com/mobz/elasticsearch-head/

启动head插件，访问9100端口

# 安装cnpm的命令

npm install -g cnpm -registry=
https://registry.npm.taobao.org

# cnpm下载资源更快

cnpm install

npm run start

IK分词器插件 https://github.com/medcl/elasticsearch-analysis-ik/releases

字段类型

官网类型文档地址：
https://www.elastic.co/guide/en/elasticsearch/reference/current/keyword.html

– 字符串类型

text、keyword

– 数值类型

long，integer，short，byte，double，float，half float，scaled float

– 日期类型

date

– te布尔值类型

boolean·

– 二进制类型

binary

– 等等……

集成Springboot

 <!--整合es-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
        </dependency>
        <!--es-->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.6.1</version>
        </dependency>
        <!--fastjson-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.80</version>
        </dependency>

配置类

@Configuration
public class ElasticSearchConfig {
    @Bean
    public RestHighLevelClient restHighLevelClient(){
        RestHighLevelClient client=new RestHighLevelClient(
                RestClient.builder(new HttpHost("127.0.0.1",9200,"http"))
        );
        return client;
    }
}

创建索引

   CreateIndexRequest index = new CreateIndexRequest("index");
        CreateIndexResponse createIndexResponse = restHighLevelClient.indices().create(index, RequestOptions.DEFAULT);

添加文档

   User user = new User("学习", 25);
        IndexRequest index = new IndexRequest("index");
        index.id("1");
        index.timeout(TimeValue.timeValueSeconds(1));
        index.source(JSON.toJSONString(user), XContentType.JSON);
        IndexResponse indexResponse = restHighLevelClient.index(index, RequestOptions.DEFAULT);
        System.out.println(indexResponse.toString());

获取文档的信息

 GetRequest getRequest = new GetRequest("index","1");
        GetResponse getResponse = restHighLevelClient.get(getRequest, RequestOptions.DEFAULT);
        System.out.println(getResponse.getSourceAsString());

批量插入数据

        BulkRequest bulkRequest = new BulkRequest();
        bulkRequest.timeout("1s");
        ArrayList<User> users = new ArrayList<>();
        users.add(new User("yu",3));
        users.add(new User("hello",3));
    
        for (int i = 0; i < users.size(); i++) {
            bulkRequest.add(new IndexRequest("index")
                    .id(""+(i+1))// 不设置id，则会生成默认id
                    .source(JSON.toJSONString(users.get(i)),XContentType.JSON));
        }
        BulkResponse bulkResponse = restHighLevelClient.bulk(bulkRequest, RequestOptions.DEFAULT);
        System.out.println(bulkResponse.hasFailures());// 是否失败，返回false代表成功
    

查询

 SearchRequest searchRequest=new SearchRequest("index");
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("name", "狂神");
        searchSourceBuilder.query(matchQueryBuilder);
        searchRequest.source(searchSourceBuilder);
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        for(SearchHit searchHit:search.getHits().getHits()){
            System.out.println(searchHit.getSourceAsMap());
        }

注：本文为学习狂神ElasticSearch视频所做的笔记，详细链接https://www.kuangstudy.com/bbs/1501584046755880962

https://www.kuangstudy.com/bbs/1552226602677882882