[大数据]使用Java Api 查询ElasticSearch 索引 每个字段的个数

import com.alibaba.fastjson.JSONObject;
import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;

import java.io.IOException;

public class ESTest_Doc_Count {

    public String suoyin_count (String args) throws IOException {
        //创建ES客户端
        RestHighLevelClient esClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        //13、统计索引中字段的个数
        SearchRequest request = new SearchRequest();
        request.indices("user");

        SearchSourceBuilder builder = new SearchSourceBuilder();
        //将传入的参数解析
        String[]  suoyin=args.split(",");
        JSONObject result = new JSONObject();

        String aggregations="";
        String agecount="";
        int value=0;
        //按照传入的参数分别统计
        for(int i=0;i<suoyin.length;i++){

            String name=suoyin[i];
            AggregationBuilder  aggregationBuilder = AggregationBuilders.count(name).field(name);
            builder.aggregation(aggregationBuilder);
            request.source(builder);
            SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
            JSONObject JSON = JSONObject.parseObject(response.toString());
            if(JSON.getString("aggregations") != null & !JSON.getString("aggregations").trim().equals("")){
                aggregations=JSON.getString("aggregations");
            }

            JSONObject JSON2 = JSONObject.parseObject(aggregations);
            if(JSON2.getString("value_count#"+name) != null & !JSON2.getString("value_count#"+name).trim().equals("")){
                agecount=JSON2.getString("value_count#"+name);
            }
            JSONObject JSON3 = JSONObject.parseObject(agecount);
            if(JSON3.getInteger("value") != null ){
                value=JSON3.getInteger("value");
            }

            result.put(name,value);

        }

        //关闭ES客户端
        esClient.close();

        return result.toString();


    }
    

    public static void main(String[] args) throws Exception {
        ESTest_Doc_Count count = new ESTest_Doc_Count();

        //查询一下索引中 age 和score 这两个字段分别有多少
       String res= count.suoyin_count("age,score");
       //输出结果
        System.out.println("res:"+res);


    }
}

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