Spring Data Elasticsearch 聚合查询

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如需要统计某件商品的数量，最高价格，最低价格等就用到了聚合查询，就像数据库中的group by

首先需要注入ElasticsearchTemplate

@Autowired
private ElasticsearchTemplate elasticsearchTemplate;

然后开始操作

//聚合
public Map<String, Integer> polymerizationQuery() {
String aggName = "popularBrand";
NativeSearchQueryBuilder queryBuilder = new NativeSearchQueryBuilder();
//聚合
queryBuilder.addAggregation(AggregationBuilders.terms("popularBrand").field("brand"));
//查询并返回带聚合结果
AggregatedPage<Item> result = elasticsearchTemplate.queryForPage(queryBuilder.build(), Item.class);
//解析聚合
Aggregations aggregations = result.getAggregations();
//获取指定名称的聚合
StringTerms terms = aggregations.get(aggName);
//获取桶
List<StringTerms.Bucket> buckets = terms.getBuckets();
//遍历打印
Map<String, Integer> map = new HashMap<>();
for (StringTerms.Bucket bucket : buckets) {
map.put(bucket.getKeyAsString(), (int) bucket.getDocCount());
System.out.println("key = " + bucket.getKeyAsString());
System.out.println("DocCount = " + bucket.getDocCount());
}
return map;
}

elasticseach的可视化数据

其他方法

（1）统计某个字段的数量
ValueCountAggregationBuilder vcb= AggregationBuilders.count("自定义").field("uid");
（2）去重统计某个字段的数量
CardinalityAggregationBuilder cb= AggregationBuilders.cardinality("distinct_count_uid").field("uid");
（3）聚合过滤
FilterAggregationBuilder fab= AggregationBuilders.filter("uid_filter").filter(QueryBuilders.queryStringQuery("uid:001"));
（4）按某个字段分组
TermsAggregationBuilder tb= AggregationBuilders.terms("group_name").field("name");
（5）求和
SumAggregationBuilder sumBuilder= AggregationBuilders.sum("sum_price").field("price");
（6）求平均
AvgAggregationBuilder ab= AggregationBuilders.avg("avg_price").field("price");
（7）求最大值
MaxAggregationBuilder mb= AggregationBuilders.max("max_price").field("price");
（8）求最小值
MinAggregationBuilder min= AggregationBuilders.min("min_price").field("price");
（9）按日期间隔分组
DateHistogramAggregationBuilder dhb= AggregationBuilders.dateHistogram("dh").field("date");
（10）获取聚合里面的结果
TopHitsBuilder thb= AggregationBuilders.topHits("top_result");
（11）嵌套的聚合
NestedAggregationBuilder nb= AggregationBuilders.nested("negsted_path").path("quests");
（12）反转嵌套
AggregationBuilders.reverseNested("res_negsted").path("kps ");