如何使用java在elasticsearch中获得subAggregation？

Question

我有一个聚合，

MetricsAggregationBuilder aggregation =
            AggregationBuilders
                    .cardinality("agg")
                    .field("age");

我有另一个包含'agg'

的聚合

FilterAggregationBuilder filterAggregationBuilder = AggregationBuilders.filter("agf");
    filterAggregationBuilder.filter(FilterBuilders.termFilter("age", 20));
    filterAggregationBuilder.subAggregation(aggregation);

我可以使用

获得agf聚合

Cardinality agg2 = searchResponse.getAggregations().get("agf");

但我怎样才能得到聚合'agg'和'agg'的值