Elasticsearch学习(4) spring boot整合Elasticsearch的聚合操作

2022-02-27 22:00:13

之前已将spring boot原生方式介绍了，接下将结介绍的是Elasticsearch聚合操作。聚合操作一般来说是解决一下复杂的业务，比如mysql中的求和和分组，由于博主踩的坑比较多，所以博客可能更多的会介绍这些坑。

一、application.properties配置文件

##端口号

server.port=8880

##es地址

spring.data.elasticsearch.cluster-nodes =127.0.0.1:9300

二、创建一个Bean层

import org.springframework.data.elasticsearch.annotations.Document;

@Document(indexName = "article",type = "center")

public class Zoo {

            private int id;

            private String animal;

            private Integer num;

            private String  breeder;

            public int getId() {

                return id;

            }

            public void setId(int id) {

                this.id = id;

            }

            public String getAnimal() {

                return animal;

            }

            public void setAnimal(String animal) {

                this.animal = animal;

            }

            public Integer getNum() {

                return num;

            }

            public void setNum(Integer num) {

                this.num = num;

            }

            public String getBreeder() {

                return breeder;

            }

            public void setBreeder(String breeder) {

                this.breeder = breeder;

            }

            public Zoo(int id, String animal, Integer num, String breeder) {

                super();

                this.id = id;

                this.animal = animal;

                this.num = num;

                this.breeder = breeder;

            }

            public Zoo() {

                super();

            }

}

bean层代码

三、创建一个dao层

import org.springframework.context.annotation.Configuration;

import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;

@Configuration

public interface ZooMapper  extends  ElasticsearchRepository<Zoo,Integer>{

}

dao层代码

四、创建一个Controller层，编写聚合代码　

import java.util.Map;

import org.elasticsearch.action.search.SearchResponse;

import org.elasticsearch.index.query.QueryBuilder;

import org.elasticsearch.index.query.QueryBuilders;

import org.elasticsearch.search.aggregations.Aggregation;

import org.elasticsearch.search.aggregations.AggregationBuilders;

import org.elasticsearch.search.aggregations.Aggregations;

import org.elasticsearch.search.aggregations.metrics.sum.InternalSum;

import org.elasticsearch.search.aggregations.metrics.sum.SumAggregationBuilder;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.data.elasticsearch.core.ElasticsearchTemplate;

import org.springframework.data.elasticsearch.core.ResultsExtractor;

import org.springframework.data.elasticsearch.core.query.NativeSearchQueryBuilder;

import org.springframework.data.elasticsearch.core.query.SearchQuery;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class UserController {

    @Autowired

    ZooMapper zooMapper;

    @Autowired

    private ElasticsearchTemplate elasticsearchTemplate;

     // 访问接口地址：localhost:8880/find

    //存储数据

    @GetMapping("find")

    public Object save(){

        //创建查询条件，这里表示查询所有文档

        QueryBuilder queryBuilder=QueryBuilders.boolQuery();

        //构造sql组装容器

         NativeSearchQueryBuilder  nativeSearchQueryBuilder =new NativeSearchQueryBuilder();

         //创建聚合条件，求和函数

         SumAggregationBuilder sumAgg = AggregationBuilders.sum("sum_num").field("num");

         //将查询条件和聚合条件放入sql组装容器中

          nativeSearchQueryBuilder.withQuery(queryBuilder);

          nativeSearchQueryBuilder.addAggregation(sumAgg);

          //封装sql组装容器

          SearchQuery  query = nativeSearchQueryBuilder.build();

          //执行sql,此时容器中的sql1为

          //select SUM(num) from zoo

          Aggregations aggregations = elasticsearchTemplate.query(query, new ResultsExtractor<Aggregations>() {

              @Override

              public Aggregations extract(SearchResponse response) {

                  return response.getAggregations();

              }

          });

          //将aggregations转换成map集合

          Map<String, Aggregation> aggregationMap = aggregations.asMap();

          //得到聚合的值，参数是自己定义的别名

          InternalSum internalSum=(InternalSum) aggregationMap.get("sum_num");

            return internalSum.getValue();

    }

}

controller层代码

在测试之前，我们需要在ES中添加索引：

访问 localhost:8880/find

本文只介绍了求和的聚合方式，至于其他聚合方式可以参考：

http://blog.csdn.net/u010454030/article/details/63266035

五、遇到的问题

　　ES中text类型无法聚合问题，错误代码：

java.lang.IllegalArgumentException: Fielddata is disabled on text fields by default. Set fielddata=true on [geoip.city_name] in order to load fielddata in memory by uninverting the inverted index. 
Note that this can however use significant memory. Alternatively use a keyword field instead.at org.elasticsearch.index.mapper.TextFieldMapper$TextFieldType.fielddataBuilder(TextFieldMapper.java:336)

解决方案：

通过get请求地址：http://127.0.0.1:9200/你的索引名/你的type名/_search

　　参数为：　　

{"你的type名字":

    {"properties":

        {"你要设置的字段名":

            {"type":"text","fielddata":true}

        }

    }

}

码农公寓

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