Elasticsearch的基本功能和使用

Elasticsearch ，简称为 ES，是一款非常强大的开源的高扩展的分布式全文 检索引擎，可以帮助我们从海量数据中快速找到需要的内容,它可以近乎实时的 存储、检索数据.还可以可以实现日志统计、分析、系统监控等功能.

官网:https://www.elastic.co/cn

例如京东,淘宝,头条等站内搜索功能.

 ES环境搭建

ES 下载地址: https://www.elastic.co/cn/downloads/elasticsearch 默认打开是最新版本 7.6.1 版下载

https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-7.6.1-windows-x86_64.zip解压

在bin目录中双击elasticsearch.bat启动

访问 http://127.0.0.1:9200

安装数据可视化界面 elasticsearch head

安装 nodejs

github 下载: https://github.com/mobz/elasticsearch-head/

github 加速器: https://github.ur1.fun/

在 config 目录中的 elasticsearch.yml 文件中配置

# 开启跨域

http.cors.enabled: true

# 所有人访问

http.cors.allow-origin: "*"

命令行进入目录（第一次安装即可）

npm install

启动可视化界面 (需要启动ES才可启动可视化界面)

npm run start

安装可视化 kibana 组件 

Kibana 是一个针对 Elasticsearch 的开源分析及可视化平台，用来搜索、查看交互 存储在 Elasticsearch 索引中的数据。

使用 Kibana，可以通过各种图表进行高级数据分析及展示。Kibana 让海量数据更 容易理解。

下载版本要和 ES 版本一致

下载地址 : https://www.elastic.co/cn/downloads/kibana 默认打开是最新版本 7.6.1 下载版

https://artifacts.elastic.co/downloads/kibana/kibana-7.6.1-windows-x86_64.zip

汉化 kibana

修改 config 目录下的 kibana.yml 文件 i18n.locale: "zh-CN"

双击 bin 目录下的 kibana.bat 启动

访问http://localhost:5601 

显示界面

SpringBoot使用ES搜索

配置类

import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

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

使用

import com.fasterxml.jackson.databind.ObjectMapper;

import com.ffyc.news.config.ElasticSearchConfig;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.indices.CreateIndexRequest;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;


import java.io.IOException;


@RestController
@RequestMapping(path = "/es")
public class EsController {
    @Autowired
    ElasticSearchConfig elasticSearchConfig;
    @GetMapping(path = "/indexOper")
    public String indexOper() throws IOException {
        //创建索引库
        CreateIndexRequest request = new CreateIndexRequest("users_index");
        elasticSearchConfig.restHighLevelClient().indices().create(request, RequestOptions.DEFAULT);
        return "success";
        //删除库
//        DeleteIndexRequest deleteIndexRequest = new DeleteIndexRequest("users");
//        AcknowledgedResponse delete = restHighLevelClient.indices().delete(deleteIndexRequest, RequestOptions.DEFAULT);
//        System.out.println(delete.isAcknowledged());

//        判断库为例
//        GetIndexRequest getIndexRequest = new GetIndexRequest("users");
//        boolean users =  restHighLevelClient.indices().exists(getIndexRequest, RequestOptions.DEFAULT);
//        System.out.println(users);

    }

    /*@GetMapping(path = "/docOper")
    public String docOper() throws IOException {
        //模拟从前端传递过来的数据
        News news = new News();
        news.setId(1);
        news.setTitle("美国今年要总统选择,拜登着急了");
        news.setImg("aaaaasssss.jpg");
        news.setContent("少时诵诗书所所所所所所所所所所所所所所所");
        news.setCount(300);

        //把News中的数据封装到NewsES
        NewsES newsES = new NewsES();
        //对象数据复制
        BeanUtils.copyProperties(news,newsES);
        //创建请求对象
        IndexRequest indexRequest  = new IndexRequest("news").id(newsES.getId().toString());
        indexRequest.source(new ObjectMapper().writeValueAsString(newsES), XContentType.JSON);
        //执行
        restHighLevelClient.index(indexRequest, RequestOptions.DEFAULT);

        return "success";
    }*/

   /* @GetMapping(path = "/docOper")
    public String docOper() throws IOException {
        //模拟从前端传递过来的数据
        News news = new News();
        news.setId(1);
        news.setTitle("中国航母开往美国,准备开战,拜登着急了");
        news.setImg("ddddddddddddddddddddd.jpg");
        news.setContent("少时诵诗书所所所所所所所所所所所所所所所");
        news.setCount(30000);

        //把News中的数据封装到NewsES
        NewsES newsES = new NewsES();
        //对象数据复制
        BeanUtils.copyProperties(news,newsES);
        //创建一个修改的请求
        UpdateRequest updateRequest = new UpdateRequest("news",newsES.getId().toString());
        updateRequest.doc(new ObjectMapper().writeValueAsString(newsES), XContentType.JSON);

        restHighLevelClient.update(updateRequest,RequestOptions.DEFAULT);
        return "success";
    }*/

  /*  @GetMapping(path = "/docOper")
    public String docOper() throws IOException {
        //创建一个修改的请求
        DeleteRequest deleteIndexRequest = new DeleteRequest("news","1");
        restHighLevelClient.delete(deleteIndexRequest,RequestOptions.DEFAULT);
        return "success";
    }*/

  /*  @GetMapping(path = "/docOper")
    public String docOper() throws IOException {
         //创建一个搜索的请求
        SearchRequest searchRequest = new SearchRequest("news");
                     //封装搜索条件
                     searchRequest.source().query(QueryBuilders.termQuery("title","免费"));
         //发送搜索请求, 接收搜索的结果
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

        ArrayList arrayList  = new ArrayList<>();
        SearchHits hits = search.getHits();
        SearchHit[] hits1 = hits.getHits();
        for (SearchHit searchHit : hits1){
             String json =    searchHit.getSourceAsString();
             NewsES newsES = new ObjectMapper().readValue(json,NewsES.class);
            arrayList.add(newsES);
        }



        return "success";
    }*/

//    @GetMapping(path = "/docOper")
//    public String docOper() throws IOException {
//        //创建一个搜索的请求
//        SearchRequest searchRequest = new SearchRequest("news");
//        //封装搜索条件
//        //设置关键字 高亮显示
//        searchRequest.source().highlighter(new HighlightBuilder().field("title").requireFieldMatch(false));
//        searchRequest.source().query(QueryBuilders.termQuery("title","免费"));
//        //发送搜索请求, 接收搜索的结果
//        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
//
//        ArrayList arrayList  = new ArrayList<>();
//        SearchHits hits = search.getHits();
//        SearchHit[] hits1 = hits.getHits();
//        for (SearchHit searchHit : hits1){
//            String json =    searchHit.getSourceAsString();
//            NewsES newsES = new ObjectMapper().readValue(json,NewsES.class);
//
//            //获取高亮名称
//            Map highlightFields = searchHit.getHighlightFields();
//            HighlightField titleField = highlightFields.get("title");
//            String highttitle = titleField.getFragments()[0].string();
//            newsES.setTitle(highttitle);//用添加了高亮的标题替换原始文档标题内容
//            arrayList.add(newsES);
//        }
//
//
//
//        return "success";
//    }
}