springboot + elasticsearch 进行Buc

aggregations 包含 bucketing metric matrix pipeline

Bucketing
A family of aggregations that build buckets, where each bucket is associated with a key and a document criterion. When the aggregation is executed, all the buckets criteria are evaluated on every document in the context and when a criterion matches, the document is considered to "fall in" the relevant bucket. By the end of the aggregation process, we’ll end up with a list of buckets - each one with a set of documents that "belong" to it.

实体类

@Data
@Document(indexName = "es-customer",
        type = "customer",
        shards = 2,
        replicas = 1, refreshInterval = "-1")
public class Customer {

    @Id
    private String id;

    @Field(type = FieldType.Keyword
           )
    private String firstName;

    private String lastName;

    private Boolean valid;

    private Integer age;

    private Date createTime;
}

es里 数据

Customer(id=4_lguWkB9U5ULlhWJ1QK, firstName=tom, lastName=001, valid=null, age=44, createTime=Tue Mar 26 17:41:20 CST 2019)
Customer(id=5PlguWkB9U5ULlhWJ1Q5, firstName=lily, lastName=002, valid=null, age=56, createTime=Tue Mar 26 17:41:20 CST 2019)
Customer(id=5flguWkB9U5ULlhWJ1Rk, firstName=lily, lastName=004, valid=null, age=53, createTime=Tue Mar 26 17:41:20 CST 2019)
Customer(id=3_lguWkB9U5ULlhWJlQy, firstName=river 1, lastName=007, valid=null, age=12, createTime=Tue Mar 26 17:41:20 CST 2019)
Customer(id=4PlguWkB9U5ULlhWJlR6, firstName=Lucy 1, lastName=001, valid=null, age=13, createTime=Tue Mar 26 17:41:20 CST 2019)
Customer(id=4flguWkB9U5ULlhWJlSp, firstName=Lucy, lastName=002, valid=null, age=22, createTime=Tue Mar 26 17:41:20 CST 2019)
Customer(id=4vlguWkB9U5ULlhWJlTc, firstName=frank, lastName=001, valid=null, age=33, createTime=Tue Mar 26 17:41:20 CST 2019)
Customer(id=5vlguWkB9U5ULlhWJ1SN, firstName=tom, lastName=002, valid=null, age=66, createTime=Tue Mar 26 17:41:20 CST 2019)
Customer(id=5_lguWkB9U5ULlhWJ1S2, firstName=tom, lastName=005, valid=null, age=33, createTime=Tue Mar 26 17:41:20 CST 2019)

进行聚合操作

 @Test
    public void aggregationTest(){
        //获取注解，通过注解可以得到 indexName 和 type
        Document document = Customer.class.getAnnotation(Document.class);
        // 构建查询 ， Aggregation 中 nameCount 为聚合的结果，firstName 为字段名称
        SearchQuery searchQuery = new NativeSearchQueryBuilder()
                .withQuery(matchAllQuery())
                .withSearchType(SearchType.QUERY_THEN_FETCH)
                .withIndices(document.indexName()).withTypes(document.type())
                .addAggregation(AggregationBuilders.terms("nameCount").field("firstName"))
                .build();

        // 聚合的结果
        Aggregations aggregations = elasticsearchTemplate.query(searchQuery, response -> response.getAggregations());
        Map<String, Aggregation> results = aggregations.asMap();
        StringTerms stringTerms= (StringTerms) results.get("nameCount");
        // 将bucket list 转换成 map ， key -> 名字   value-> 出现次数
        Map<String,Long> nameCountMap = stringTerms.getBuckets()
                .stream()
                .collect(Collectors.toMap(
                        StringTerms.Bucket::getKeyAsString,
                        InternalTerms.Bucket::getDocCount,
                        (x,y)->x)
                );
        System.out.println(nameCountMap);

    }

返回结果

{frank=1, tom=3, lily=2, Lucy=1, river 1=1, Lucy 1=1}

参考地址
https://www.elastic.co/guide/en/elasticsearch/reference/6.3/search-aggregations.html#search-aggregations
https://blog.csdn.net/Topdandan/article/details/81436141
https://my.oschina.net/u/3664884/blog/1814423