RestHighLevelClient v/s ElasticsearchClient Java client in Elasticsearch 8.x to search

Question

I have used RestHighLevelClient to search and retrieve data as List<Map<String, Object>>.

final SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);
    RestStatus statusCode = response.status();
    log.info("Status code : {} ", statusCode.getStatus());
    if(RestStatus.OK.equals(response.status())) {
        final SearchHits hits = response.getHits();
        Long totalHits = hits.getTotalHits();
        log.info("Total number of hits : {} ", totalHits);
        final SearchHit[] results = hits.getHits();
        List<Map<String, Object>> list = new ArrayList<>(totalHits.intValue());
        for(SearchHit hit : results) {
            final Map<String, Object> sourceAsMap = hit.getSourceAsMap();
            list.add(sourceAsMap);
        }
        return list;
    }

The signature of search() in ElasticSearchClient is different. It requires to provide Class as a part of the method parameter. In my case, I do not want to cast it into any concrete object. I tried to use "Object.class" (e.g. elasticSearchClient.search(searchRequest, Object.class). But It did not provide me the list of Map which I used to get in RestHighLevelClient. My question is how do I extract the List<Map <String, Object>> from the response using the new API?

 SearchResponse<Object> response = elasticSearchClient.search(searchRequest, Object.class);
        List<Hit<Object>> hits = response.hits().hits();
        for (Hit<Object> hit : hits) {
            // how do I get Map<String, Object> here? 
        }

Answer 1

You can also use the ObjectNode class:

ObjectNode json = response.source();
String name = json.get("name").asText();
logger.info("Product name " + name);

Source: documentation