elasticsearch聚合查询实例，elasticsearch聚合,现有索引数据：index

elasticsearch聚合查询实例，elasticsearch聚合,现有索引数据：index

现有索引数据：

index:schooltype:student---------------------------------------------------{"grade":"1", "class":"1", "name":"xiao 1"}{"grade":"1", "class":"1", "name":"xiao 2"}{"grade":"1", "class":"2", "name":"xiao 3"}{"grade":"1", "class":"2", "name":"xiao 4"}{"grade":"1", "class":"2", "name":"xiao 5"}

Java分组统计年级和班级学生个数，如SQL: SELECT grade,class,count(1) FROM student GROUP BY grade,class;

package test;import java.util.Iterator;import java.util.Map;import org.elasticsearch.action.search.SearchRequestBuilder;import org.elasticsearch.action.search.SearchResponse;import org.elasticsearch.action.search.SearchType;import org.elasticsearch.search.aggregations.Aggregation;import org.elasticsearch.search.aggregations.AggregationBuilders;import org.elasticsearch.search.aggregations.bucket.terms.StringTerms;import org.elasticsearch.search.aggregations.bucket.terms.Terms.Bucket;import org.elasticsearch.search.aggregations.bucket.terms.TermsBuilder;import org.junit.Test;import utils.NesUtils;public class TestAggregation{    @Test    public void testAggregation()    {        SearchRequestBuilder srb = NesUtils.getSearcher("school");        srb.setTypes("student");        srb.setSearchType(SearchType.COUNT);        TermsBuilder gradeTermsBuilder = AggregationBuilders.terms("gradeAgg").field("grade");        TermsBuilder classTermsBuilder = AggregationBuilders.terms("classAgg").field("class");        gradeTermsBuilder.subAggregation(classTermsBuilder);        srb.addAggregation(gradeTermsBuilder);        SearchResponse sr = srb.execute().actionGet();        Map<String, Aggregation> aggMap = sr.getAggregations().asMap();        StringTerms gradeTerms = (StringTerms) aggMap.get("gradeAgg");        Iterator<Bucket> gradeBucketIt = gradeTerms.getBuckets().iterator();        while(gradeBucketIt.hasNext())        {            Bucket gradeBucket = gradeBucketIt.next();            System.out.println(gradeBucket.getKey() + "年级有" + gradeBucket.getDocCount() +"个学生。");            StringTerms classTerms = (StringTerms) gradeBucket.getAggregations().asMap().get("classAgg");            Iterator<Bucket> classBucketIt = classTerms.getBuckets().iterator();            while(classBucketIt.hasNext())            {                Bucket classBucket = classBucketIt.next();                System.out.println(gradeBucket.getKey() + "年级" +classBucket.getKey() + "班有" + classBucket.getDocCount() +"个学生。");            }            System.out.println();        }    }}

运行完成输出结果

---------------------------------------------------1年级有5个学生。1年级2班有3个学生。1年级1班有2个学生。