java Elasticsearch 进行嵌套子聚合
聚合子查询:
TermsAggregationBuilder aggregation = AggregationBuilders.terms("dt_id").field("dt_ids").size(30000); String agg_area_field = "city_code"; TermsAggregationBuilder area_field_builder = AggregationBuilders.terms("area_field").field(agg_area_field).size(30000); area_field_builder.subAggregation(aggregation); SearchResponse response = client.prepareSearch(index_name).setTypes("lw_devices") .setQuery(boolQuery) .addAggregation(area_field_builder) .execute() .actionGet();
以上demo的大致的意思就是,先对city_code字段进行聚合,然后对聚合结果,再用dt_ids字段进行嵌套聚合(子聚合) , 相当于sql的两个group by , 一个聚合嵌套于另一个聚合之内,可以用subAggregation方法进行关联。
然后就是对聚合结果的遍历:
Terms terms = response.getAggregations().get("area_field"); List<Terms.Bucket> buckets = terms.getBuckets();for (Terms.Bucket bucket : buckets) { //地区 String code = (String) bucket.getKey(); System.out.println(code); Aggregations aggregations = bucket.getAggregations(); Terms dt_id = aggregations.get("dt_id"); List<Terms.Bucket> buckets1 = dt_id.getBuckets(); for (Terms.Bucket bucket1 : buckets1) { System.out.println(bucket1.getKey() + ":" + bucket1.getDocCount()); } }
思路就是,先根据response拿到aggregation,然后根据标识符拿到对应的,聚合类型,然后得到bucket的集合。然后再通过bucket拿到aggregation, 然后以此循环往下提取聚合结果。