ElasticsearchTemplate 查詢獲取單個字段

        return elasticsearchTemplate.query(nativeSearchQuery, new ResultsExtractor<List<Long>>() {
            @Override
            public List<Long> extract(SearchResponse response) {
                List<Long> result = new ArrayList<>();
                for (SearchHit hit : response.getHits()) {
                    result.add(hit.getSource().get("user_naem").toString());
                }
                return result;
            }
        });