Elasticsearch7.6.2 RestHighLevelClient查询用法 must should（and or 关系）

1. 引入jar

        <dependency>

            <groupId>org.elasticsearch.client</groupId>

            <artifactId>elasticsearch-rest-high-level-client</artifactId>

            <version>7.6.2</version>

        </dependency>

2. 初始化RestHighLevelClient

@Configuration

public class ElasticSearchClientConfig {

    @Value("${es.hostname}")

    private String hostname;

    @Value("${es.port}")

    private Integer port;

    @Value("${es.scheme}")

    private String scheme;

    @Bean("esClient")

    public RestHighLevelClient esClient(){

        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(new HttpHost(hostname, port, scheme)));

        return client;

    }

}

4. 查询

@Slf4j

@Component

public class MzChangeLogDao {

	@Value("${mk.mz.changLog.index}")

	private String indexName;

	@Autowired

	@Qualifier("esClient")

	private RestHighLevelClient restHighLevelClient;

	public List<Object> queryChangeLog(String table, String dbName, String elementsId, String idField) {

		SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();

		BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();

		boolQueryBuilder.must(QueryBuilders.matchQuery("fieldA", table));

		boolQueryBuilder.must(QueryBuilders.matchQuery("filedB",  dbName));

		if (StringUtils.isNotBlank(elementsId)) {

			BoolQueryBuilder shouldQueryBuilder = QueryBuilders.boolQuery();

			String[] idFiledArr = idField.split(",");

			for (String id : idFiledArr) {

				shouldQueryBuilder.should(QueryBuilders.matchQuery(id,  elementsId));

			}

			boolQueryBuilder.must(shouldQueryBuilder);

		}

		searchSourceBuilder.query(boolQueryBuilder);

		searchSourceBuilder.from(0);

		searchSourceBuilder.size(100);

		searchSourceBuilder.sort(new FieldSortBuilder("log_time").order(SortOrder.DESC));

		SearchRequest searchRequest = new SearchRequest(indexName);

		searchRequest.source(searchSourceBuilder);

		SearchResponse searchResponse = null;

		try {

			searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

		} catch (Exception e) {

			// 这里有可能会抛ElasticsearchException,比如没索引 没字段啥的

			log.error("请求ES出错: ", e);

			throw new BizException("请求ES出错: ", e);

		}

		List<Object> retList = new ArrayList<>();

		// 根据状态和数据条数验证是否返回了数据

		if (RestStatus.OK.equals(searchResponse.status()) && searchResponse.getHits().getTotalHits().value > 0) {

			SearchHits hits = searchResponse.getHits();

			for (SearchHit hit : hits) {

				// 将 JSON 转换成对象

				//UserInfo userInfo = JSON.parseObject(hit.getSourceAsString(), UserInfo.class);

				Object json = JSONObject.parse(hit.getSourceAsString());

				retList.add(json);

			}

		}

		return retList;

	}

}

5. must should 解释

用 mysql语法 举例比如 要查询

 where fieldA = 'aaaa' and filedB = 'bbbbb' and (filedC = 'c1' or filedC = 'c2');

对于上述查询，针对ES： RestHighLevelClient查询的写法为利用 must 和 should 配合：

SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();

BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();

boolQueryBuilder.must(QueryBuilders.matchQuery("fieldA", "aaaa"));

boolQueryBuilder.must(QueryBuilders.matchQuery("filedB",  "bbbb"));

BoolQueryBuilder shouldQueryBuilder = QueryBuilders.boolQuery();

shouldQueryBuilder.should("filedC", "c1");

shouldQueryBuilder.should("filedC", "c2");

boolQueryBuilder.must(shouldQueryBuilder);

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