Elasticsearch/ES教程（18）：RestClient查询Match/Term/Range/Bool

Elasticsearch 是一个非常强大的搜索引擎。它目前被广泛地使用于各个 IT 公司。Elasticsearch 是由 Elastic 公司创建。它的代码位于 GitHub - elastic/elasticsearch: Free and Open, Distributed, RESTful Search Engine。目前，Elasticsearch 是一个免费及开放（free and open）的项目。同时，Elastic 公司也拥有 Logstash 及 Kibana 开源项目。这个三个项目组合在一起，就形成了 ELK 软件栈。他们三个共同形成了一个强大的生态圈。简单地说，Logstash 负责数据的采集，处理（丰富数据，数据转换等），Kibana 负责数据展示，分析，管理，监督及应用。Elasticsearch 处于最核心的位置，它可以帮我们对数据进行快速地搜索及分析。

package cn.bdbk.hotel;

import cn.bdbk.hotel.pojo.HotelDoc;
import com.alibaba.fastjson.JSON;
import org.apache.http.HttpHost;
import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.indices.CreateIndexRequest;
import org.elasticsearch.client.indices.GetIndexRequest;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import java.io.IOException;


public class HotelSearchTest {

    private RestHighLevelClient client;

    @Test
    void testMatch() throws IOException {
        //准备request
        SearchRequest request = new SearchRequest("hotel");
        //准备dsl
        request.source().query(QueryBuilders.matchQuery("name", "如家"));
        //发送请求
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
        //解析响应
        handleResponse(response);
    }


    //布尔查询
    @Test
    void testBool() throws IOException {
        //准备request
        SearchRequest request = new SearchRequest("hotel");
        //准备dsl
        BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();

        boolQueryBuilder.must(QueryBuilders.termQuery("city", "杭州"));
        //boolQueryBuilder.filter(QueryBuilders.rangeQuery("price").gte(10));
        request.source().query(boolQueryBuilder);
        //发送请求
        SearchResponse response = client.search(request, RequestOptions.DEFAULT);
        //解析响应
        handleResponse(response);
    }

    private void handleResponse(SearchResponse response) {
        //解析响应
        SearchHits searchHits = response.getHits();
        //获取总条数
        long total = searchHits.getTotalHits().value;
        //获取文档数组
        SearchHit[] searchHit = searchHits.getHits();
        for (SearchHit hit : searchHit){
            //获取文档source
            String json = hit.getSourceAsString();
            //反序列化
            HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
            System.out.println(hotelDoc);
        }
    }

    @BeforeEach
    void setUP(){
        this.client = new RestHighLevelClient(RestClient.builder(
                HttpHost.create("http://170.106.116.159:9200")
        ));
    }

    @AfterEach
    void tearTown() throws IOException {
        this.client.close();
    }

}