RestClient查询文档快速入门

1.1、match_all

package cn.mannor.hotel;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.QueryBuilders;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;import java.io.IOException;import static cn.mannor.hotel.constants.HotelConstants.MAPPING_TEMPLATE;public class HotelSearchTest {private RestHighLevelClient restHighLevelClient; // 高级REST客户端，用于与Elasticsearch进行交互@Testvoid testMatchAll() throws IOException {//1.准备RequestSearchRequest hotelRequest = new SearchRequest("hotel");//2.准备DSLhotelRequest.source().query(QueryBuilders.matchAllQuery());//3.发送请求SearchResponse response = restHighLevelClient.search(hotelRequest, RequestOptions.DEFAULT);System.out.println(response);}/*** 初始化测试环境，创建并配置RestHighLevelClient实例。*/@BeforeEachvoid setUp() {this.restHighLevelClient = new RestHighLevelClient(RestClient.builder(HttpHost.create("http://192.168.12.131:9200") // 设置Elasticsearch的地址和端口));}/*** 测试结束后清理资源，关闭RestHighLevelClient实例。** @throws IOException 如果关闭客户端时发生IO错误*/@AfterEachvoid tearDown() throws IOException {this.restHighLevelClient.close(); // 关闭高级REST客户端，释放资源}
}

注：下面的内容我只会放置测试方法。

完整获取：

    @Testvoid testMatchAll() throws IOException {//1.准备RequestSearchRequest hotelRequest = new SearchRequest("hotel");//2.准备DSLhotelRequest.source().query(QueryBuilders.matchAllQuery());//3.发送请求SearchResponse response = restHighLevelClient.search(hotelRequest, RequestOptions.DEFAULT);//4.解析响应SearchHits searchHits = response.getHits();//4.1获取总条数long total = searchHits.getTotalHits().value;//4.2文档数组SearchHit[] hits = searchHits.getHits();//4.3遍历for (SearchHit hit : hits) {//获取文档sourceString json = hit.getSourceAsString();//反序列化HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);System.out.println("hoteldoc:" + hotelDoc);}System.out.println(response);}

其中，核心API包含所有方法：

1. hotelRequest.source()
   

2. QueryBuilders
   

1.2、全文检索查询

// 单字段查询
QueryBuilders.matchQuery("name", "上海");
// 多字段查询 
QueryBuilders.multiMatchQuery("如家", "name", "business");

1.3、精确查询

// 词条查询
QueryBuilders.termQuery("city", "杭州"); 
// 范围查询
QueryBuilders.rangeQuery("price").gte(100).lte(150);

例如：

    @Testvoid testMatch() throws IOException {//1.准备RequestSearchRequest hotelRequest = new SearchRequest("hotel");//2.准备DSL//2.1词条查询hotelRequest.source().query(QueryBuilders.termQuery("hotelName", "酒店"));//2.2范围查询// hotelRequest.source().query(QueryBuilders.rangeQuery("price").lt(300).gt(1000));//3.发送请求SearchResponse response = restHighLevelClient.search(hotelRequest, RequestOptions.DEFAULT);//4.解析响应（方法抽出来了）handelResponse(response);}

1.4、复合查询-boolean query

// 创建布尔查询
BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
// 添加must条件
boolQuery.must(QueryBuilders.termQuery("city", "杭州")); 
// 添加filter条件
boolQuery.filter(QueryBuilders.rangeQuery("price").lte(250));

例：

@Test
void testBooleQuery() throws IOException {//1.准备RequestSearchRequest hotelRequest = new SearchRequest("hotel");//2.准备DSLBoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();// 添加must条件boolQueryBuilder.must(QueryBuilders.matchQuery("city", "上海"));// 添加filter条件boolQueryBuilder.filter(QueryBuilders.rangeQuery("price").lt(250));hotelRequest.source().query(boolQueryBuilder);//3.发送请求SearchResponse response = restHighLevelClient.search(hotelRequest, RequestOptions.DEFAULT);//4.解析响应（方法抽出来了）handelResponse(response);
}

基于上述几种查询，只需要记住核心API：QueryBuilders

1.5、排序和分页

@Test
void testPageAndSort() throws IOException {//页码，每页大小int page = 1, size = 5;//1.准备RequestSearchRequest hotelRequest = new SearchRequest("hotel");//2.准备DSLhotelRequest.source().query(QueryBuilders.matchAllQuery());//分页from ,size  排序sorthotelRequest.source().from((page-1)*size).size(5).sort("price", SortOrder.DESC);//3.发送请求SearchResponse response = restHighLevelClient.search(hotelRequest, RequestOptions.DEFAULT);//4.解析响应handelResponse(response);}

1.6、高亮（解析查询高亮结果）

@Test
void testHighlight() throws IOException {//1.准备RequestSearchRequest hotelRequest = new SearchRequest("hotel");//2.准备DSLhotelRequest.source().query(QueryBuilders.matchQuery("name", "酒店"));//分页from ,size  排序sorthotelRequest.source().highlighter(new HighlightBuilder().field("name").requireFieldMatch(false));//3.发送请求SearchResponse response = restHighLevelClient.search(hotelRequest, RequestOptions.DEFAULT);//高亮解析//4.解析响应SearchHits searchHits = response.getHits();//4.1获取总条数long total = searchHits.getTotalHits().value;System.out.println("查询到的数据总条数为：" + total);//4.2文档数组SearchHit[] hits = searchHits.getHits();//4.3遍历for (SearchHit hit : hits) {//获取文档sourceString json = hit.getSourceAsString();//反序列化HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);//获取高亮结果Map<String, HighlightField> highlightFields = hit.getHighlightFields();if (!CollectionUtils.isEmpty(highlightFields)) {// 根据字段名获取高亮结果HighlightField highlightField = highlightFields.get("name");if (highlightField != null) {//获取高亮值String name = highlightField.getFragments()[0].string();//覆盖非高亮结果hotelDoc.setName(name);}}System.out.println("hoteldoc:" + hotelDoc);}System.out.println(response);
}

查询结果：