Elasticsearch Java API(十一)--聚合(aggregations)

2019-11-08 01:20:32

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Elasticsearch分析聚合介绍了分析聚合的REST命令，这篇博客介绍一下如何使用java API。

一、准备数据

测试数据请参考我的上一篇博客:Elasticsearch分析聚合。

二、需求

查询title中包含关键字”程序”的文档，统计查询按编程语言分组，统计每组的文档数量。

三、REST命令行

REST命令行如下，有三部分，query查询所有title中包含关键词程序的文档，size指定返回结果中文档数量，其值为0只返回聚合的结果，aggs部分通过language字段进行分组。

GET books/_search{ "query": { "match": { "title": "程序" } }, "size": 0, "aggs": { "per_count": { "terms": { "field": "language" } } }}

查询结果如下:

{ "took": 5, "timed_out": false, "_shards": { "total": 5, "successful": 5, "failed": 0 }, "hits": { "total": 2, "max_score": 0, "hits": [] }, "aggregations": { "per_count": { "doc_count_error_upper_bound": 0, "sum_other_doc_count": 0, "buckets": [ { "key": "java", "doc_count": 1 }, { "key": "javascript", "doc_count": 1 } ] } }}

四、聚合的JAVA API

//创建TransportClient对象 client=EsUtils.getEsClient(); QueryBuilder matchQuery = QueryBuilders.matchQuery("title", "程序"); AbstractAggregationBuilder aggregation = AggregationBuilders.terms("per_count").field("language"); SearchResponse response = client.PRepareSearch("books").setTypes("IT") .setQuery(matchQuery) .addAggregation(aggregation) .execute() .actionGet(); SearchHits hits = response.getHits(); for(SearchHit hit:hits){ System.out.println("id:"+hit.getId()+"/ttitle:"+hit.getSource().get("title")); } Terms terms = response.getAggregations().get("per_count"); List<Bucket> buckets = terms.getBuckets(); for(Bucket bucket:buckets){ System.out.println(bucket.getKey()+"----"+bucket.getDocCount()); } client.close();

运行结果:

id:2 title:Java程序性能优化id:5 title:Javascript高级程序设计java----1javascript----1