从ElasticSearch 7.3中获取字段。 Springboot Java文档

Question

我正在使用以下Java代码查询elasticsearch 7.3并获取1个文档。我将其设置为仅具有最高分数的1个文档。一切正常，文档还给我。

  @Autowired
    RestHighLevelClient client;

    @RequestMapping(value = "/search", method = RequestMethod.GET)
    public @ResponseBody
    String getItem(@RequestParam("string") String string) throws IOException {


        QueryBuilder matchQueryBuilder = QueryBuilders.simpleQueryStringQuery(string);
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.query(matchQueryBuilder);
        sourceBuilder.from(0);
        sourceBuilder.size(1);
        sourceBuilder.timeout(new TimeValue(60, TimeUnit.SECONDS));

        SearchRequest searchRequest = new SearchRequest("nutrients");
        searchRequest.source(sourceBuilder);

        SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);

        return searchResponse.toString();
    }

响应如下，我想使用Calories , Fat , Protein , Carbohydrate的Java代码访问值，而忽略其他Nutrient的值。 我需要使用String caloriesVar=153 kcal之类的4个变量中的值，而其他3个变量也需要类似的值。

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