Elasticsearch Java REST高级客户端SearchApi

矫情吗；* 2021-11-29 16:10 392阅读 0赞

Elasticsearch Java REST高级客户端SearchApi

版本：Elasticsearch 7.2.0

本节讲述一下Elasticsearch的条件搜索、排序、分组和聚合，以几个例子简单实现以下操作

1.matchAllQuery查询

2.matchQuery查询

3.termQuery查询

4.聚合操作aggregation

5.创建和关闭客户端

6.maven

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1.matchAllQuery查询

  1. /**
  2.      * matchAll查询
  3.      */
  4.     public static void matchAllQuery() {
  5.         RestHighLevelClient client = getClient();
  7.         // 这里可以不指定索引，也可以指定多个
  8.         SearchRequest searchRequest = new SearchRequest("movies");
  9.         SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  10.         searchRequest.source(searchSourceBuilder);
  11.         searchSourceBuilder.query(QueryBuilders.matchAllQuery());
  12.         // 从第一条开始,包括第一条
  13.         searchSourceBuilder.from(0);
  14.         // 查询30条
  15.         searchSourceBuilder.size(3);
  16.         // 先按year倒排
  17.         searchSourceBuilder.sort(SortBuilders.fieldSort("year").order(SortOrder.DESC));
  18.         // 再按id正排
  19.         searchSourceBuilder.sort("id");
  20.         SearchResponse search = null;
  21.         try {
  22.             search = client.search(searchRequest, RequestOptions.DEFAULT);
  23.         } catch (IOException e) {
  24.             e.printStackTrace();
  25.         }
  26.         search.getHits().forEach(System.out::println);
  27.         close(client);
  28.     }

2.matchQuery查询

  1. /**
  2.      * match查询
  3.      */
  4.     public static void matchQuery() {
  5.         RestHighLevelClient client = getClient();
  7.         // 这里可以不指定索引，也可以指定多个
  8.         SearchRequest searchRequest = new SearchRequest("movies");
  9.         SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  10.         searchRequest.source(searchSourceBuilder);
  11.         MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("title", "you life");
  12.         searchSourceBuilder.query(matchQueryBuilder);
  13. //        // 模糊查询
  14. //        matchQueryBuilder.fuzziness(Fuzziness.AUTO);
  15. //        // 前缀查询的长度
  16. //        matchQueryBuilder.prefixLength(3);
  17. //        // max expansion 选项，用来控制模糊查询
  18. //        matchQueryBuilder.maxExpansions(10);
  19.         searchSourceBuilder.from(0);
  20.         searchSourceBuilder.size(32);
  21.         // 按评分排序
  22.         searchSourceBuilder.sort("_score");
  23.         SearchResponse search = null;
  24.         try {
  25.             search = client.search(searchRequest, RequestOptions.DEFAULT);
  26.             search.getHits().forEach(System.out::println);
  27.         } catch (IOException e) {
  28.             e.printStackTrace();
  29.         } finally {
  30.             close(client);
  31.         }
  32.     }

3.termQuery查询

  1. public static void termQuery() {
  2.         RestHighLevelClient client = getClient();
  3.         SearchRequest request = new SearchRequest("movies");
  4.         SearchSourceBuilder builder = new SearchSourceBuilder();
  5.         request.source(builder);
  6.         builder.from(0);
  7.         builder.size(5);
  8.         builder.query(QueryBuilders.termQuery("title", "you"));
  9.         SearchResponse search = null;
  10.         try {
  11.             search = client.search(request, RequestOptions.DEFAULT);
  12.         } catch (IOException e) {
  13.             e.printStackTrace();
  14.         }
  15.         search.getHits().forEach(System.out::println);
  17.         close(client);
  18.     }

4.聚合操作aggregation

  1. public static void aggregation() {
  2.         RestHighLevelClient client = getClient();
  4.         SearchRequest request = new SearchRequest("movies");
  5.         SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  6.         AvgAggregationBuilder avg = AggregationBuilders.avg("id_avg").field("id");
  7.         MaxAggregationBuilder max = AggregationBuilders.max("id_max").field("id");
  8.         MinAggregationBuilder min = AggregationBuilders.min("id_min").field("id");
  9.         TermsAggregationBuilder group = AggregationBuilders.terms("year_group").field("year");
  10.         group.subAggregation(avg).subAggregation(max).subAggregation(min);
  11.         searchSourceBuilder.profile(true);
  12.         searchSourceBuilder.aggregation(group);
  13.         request.source(searchSourceBuilder);
  14.         SearchResponse search = null;
  15.         try {
  16.             search = client.search(request, RequestOptions.DEFAULT);
  17.             Aggregations aggregations = search.getAggregations();
  18.             Terms terms = aggregations.get("year_group");
  19.             //打印全部分组
  20.             terms.getBuckets().forEach( bucket ->
  21.                 bucket.getAggregations().asMap().forEach((k,v) -> 
  22.                     System.out.println(bucket.getKeyAsString()+"---" +k + "->" + ((SingleValue)v).value()))
  23.                     );
  24.             //只打印2000年的内容
  25.             String year = "2000";
  26.             Bucket bucket = terms.getBucketByKey(year);
  27.             SingleValue maxAgg = bucket.getAggregations().get("id_max");
  28.             SingleValue avgAgg = bucket.getAggregations().get("id_avg");
  29.             SingleValue minAgg = bucket.getAggregations().get("id_min");
  30.             System.out.println(year+"年最大id:"+maxAgg.value());
  31.             System.out.println(year+"年平均id:"+avgAgg.value());
  32.             System.out.println(year+"年最小id:"+minAgg.value());
  33.         } catch (IOException e) {
  34.             e.printStackTrace();
  35.         }finally {
  36.             close(client);
  37.         }
  38.     }

5.创建和关闭客户端

  1. /**
  3.      * 关闭客户端
  4.      * 
  5.      * @param client
  6.      */
  7.     private static void close(RestHighLevelClient client) {
  8.         try {
  9.             client.close();
  10.         } catch (IOException e) {
  11.             e.printStackTrace();
  12.         }
  13.     }
  15.     /**
  16.      * 获取客户端
  17.      * 
  18.      * @return
  19.      */
  20.     private static RestHighLevelClient getClient() {
  21.         RestHighLevelClient client = new RestHighLevelClient(
  22.                 RestClient.builder(new HttpHost("elk-node01", 9200, "http"), new HttpHost("elk-node02", 9200, "http"),
  23.                         new HttpHost("elk-node03", 9200, "http")));
  24.         return client;
  25.     }

6.maven

  1. <dependency>
  2.             <groupId>org.elasticsearch.plugin</groupId>
  3.             <artifactId>x-pack-sql-jdbc</artifactId>
  4.             <version>7.2.0</version>
  5. <!--             <version>6.7.1</version> -->
  6.         </dependency>
  8.         <dependency>
  9.             <groupId>org.elasticsearch.client</groupId>
  10.             <artifactId>elasticsearch-rest-high-level-client</artifactId>
  11.             <version>7.2.0</version>
  12. <!--             <version>6.7.1</version> -->
  13.         </dependency>

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