Shows how to do aggregations in Elasticsearch via the Java api

RestHighLevelClientAggregationExample.java

import org.apache.http.HttpHost;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.aggregations.metrics.sum.Sum;
import org.elasticsearch.search.builder.SearchSourceBuilder;

public class RestHighLevelClientAggregationExample {
    private static final String INDEX = "your-es-index";
    public static final String YOUR_INDEX_TYPE = "your-index-type";
    public static final String HOST = "your-host";
    public static final int PORT = 9200;

    public static void main(String[] args) throws Exception {
        RestClient restClient = RestClient.builder(new HttpHost(HOST, PORT, "http")).build();
        RestHighLevelClient restHighLevelClient = new RestHighLevelClient(restClient);

        SearchRequest searchRequest = new SearchRequest(INDEX);
        searchRequest.types(YOUR_INDEX_TYPE);
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        searchSourceBuilder.aggregation(AggregationBuilders.sum("suma").field("numericField"));
        searchSourceBuilder.query(QueryBuilders.matchAllQuery());
        // Brings only the result of the aggregation (optional)
        searchSourceBuilder.size(0);
        searchRequest.source(searchSourceBuilder);

        final SearchResponse response = restHighLevelClient.search(searchRequest);
        Sum suma = response.getAggregations().get("suma");
        System.out.println("Response = " + suma.getValue());
    }
}