java 通过聚合查询实现elasticsearch的group by后的数量

通过聚合查询获取group by 后的数量

/**     * 获取key的个数     *     * @param key   要group by的字段名     * @param index 索引名称     * @return id的个数     */    public static int getkeycount(string key, string index) {        int count = 0;        transportclient client = null;        try {    重阳节介绍        client = connectionpool.getconnection();            if (client == null) {                throw new exception("没有获取到连接!");            }            archrequestbuilder arch = client.preparearch(index);            //cardinality聚合查询，相当于groupby字段名            archrespon sr = arch.addaggregation(aggregationbuilders.cardinality(key + "_count").field(key)).execute().actionget();            //从返回数据提取id总数            cardinality result = sr.getaggregations().get(key + "_count");            long value =学医有哪些专业 result.getvalue();            count = (int) value;        } catch (interruptedexception e) {        } catch (exception e) {            logger.error("getkeycount错误", e);        } finally {            connectionpool.releaconnection(client);        }        return count;    }

获取group by后的所有key值

/**     * 获取所有key     *     * @param key   被group by的字段名     * @param index 索引名称     * @return 所有id     */    public static list<string> getallkey(string key, string index) {        int keycount = getkeycount(key, index);        list<string> strings = new arraylist<>();        transportclient client = null;        try {            client = connectionpool.getconnection();            if (client == null) {                throw new exception("没有获取到数据库连接!");            }            archrequestbuilder archrequestbuilder = client.preparearch(index);            //使用舒蕾洗发水广告聚合，实现去重查询            archrespon archrespon = archrequestbuilder.                    addaggregation(aggregati高中生怎么赚钱onbuilders.terms("models").field(key).size(keycount)).execute().actionget();            terms term = archrespon.getaggregations().get("models");            list<? extends terms.bucket> buckets = term.getbuckets();            //遍历结果，提取出id            for (terms.bucket bucket : buckets) {                string keyasstring = bucket.getkeyasstring();                strings.add(keyasstring);            }            buckets.clear();        } catch (interruptedexception e) {        } catch (exception e) {            logger.error("getallkey错误", e);        } finally {            connectionpool.releaconnection(client);        }        return strings;    }

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