如何在Elasticsearch中使用RestHighLevelClient获得不同的值？

Question

我在这里看到了你们为下面给出的链接提供解决方案的帖子。ElasticSearch Java API从查询生成器中获取不同的值

有没有办法通过org获得不同的电子邮件。弹性搜索。客户RestHighLevelClient？你能帮我解决这个问题吗？我试了很多方法，但都没能解决。但我可以在SQL Workbench中实现同样的功能，下面使用Kibana translator给出了等效的json查询。

SELECT DISTINCT email_client.keyword
FROM email_reference;

等效Elasticsearch查询如下：

{
  "from": 0,
  "size": 0,
  "_source": {
    "includes": ["email_client.keyword"],
    "excludes": []
  },
  "stored_fields": "email_client.keyword",
  "aggregations": {
    "email_client.keyword": {
      "terms": {
        "field": "email_client.keyword",
        "size": 200,
        "min_doc_count": 1,
        "shard_min_doc_count": 0,
        "show_term_doc_count_error": false,
        "order": [
          {
            "_count": "desc"
          },
          {
            "_key": "asc"
          }
        ]
      }
    }
  }
}

所以现在我想形成这个JSON查询使用RestHighLevelClient，我已经尝试过，但问题是准备搜索（）是不是有在RestHighLevelClient有任何其他实现使用RestHighLevelClient？

Answer 1

对于7.11.2版本的elasticsearch-rest-高级-客户端，下面的例子对我有效。您需要为带有关键字的字段设置聚合。

    private List<String> queryForDistinctMetadata(String aggregationKey, String field) throws IOException {

        var aggregationBuilder = AggregationBuilders
                .terms(aggregationKey)
                .field(field);

        var searchSourceBuilder = new SearchSourceBuilder()
                .aggregation(aggregationBuilder)
                .size(0);

        var searchRequest = new SearchRequest()
                .indices("<your index here>")
                .source(searchSourceBuilder);

        var response = client.search(searchRequest, RequestOptions.DEFAULT);

        var aggregation = (ParsedStringTerms) response.getAggregations().get(aggregationKey);

        return aggregation.getBuckets()
                .parallelStream()
                .map(Terms.Bucket::getKeyAsString)
                .collect(Collectors.toList());
    }

Answer 2

这应该适用于RestHighLevelClient：

        MultiSearchRequest multiRequest = new MultiSearchRequest();
        SearchRequest searchRequest = new SearchRequest();
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        searchSourceBuilder.size(0); // return only aggregation results
        searchSourceBuilder.aggregation(AggregationBuilders.terms("label_agg").field("email_client.keyword").size(200));
        searchRequest.indices("email_reference"); // index name
        searchRequest.source(searchSourceBuilder);
        multiRequest.add(searchRequest);
        MultiSearchResponse response = restHighLevelClient.msearch(multiRequest, RequestOptions.DEFAULT);