Spring Data Elasticsearch 聚合查询

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
    @Test
    public void polymerizationQuery() {
        NativeSearchQueryBuilder builder = new NativeSearchQueryBuilder();
        //terms表示有多少种类型以及每种类型的数量，此处是以手机的品牌来分组
        ValuesSourceAggregationBuilder s = AggregationBuilders.terms("brands").field("brand");
        builder.addAggregation(s);
        Aggregations aggregations = elasticsearchTemplate.query(builder.build(), new ResultsExtractor<Aggregations>() {
            @Override
            public Aggregations extract(SearchResponse searchResponse) {
                return searchResponse.getAggregations();
            }
        });
        Map<String, Aggregation> stringAggregationMap = aggregations.asMap();
        System.out.println(stringAggregationMap.get("brands"));

    }

　　结果

 　　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 ");

　　注：使用聚合查询时不能使用分词，因此字段需要设置为type = FieldType.Keyword