如何在spring boot中获取索引的json作为响应？

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
</dependency>

@Configuration
@EnableElasticsearchRepositories(basePackages = "com.example.repository")
public class ElasticsearchConfig {

    @Value("${elasticsearch.host}")
    private String host;

    @Value("${elasticsearch.port}")
    private int port;

    @Bean
    public RestHighLevelClient elasticsearchClient() {
        RestClientBuilder builder = RestClient.builder(new HttpHost(host, port));
        RestHighLevelClient client = new RestHighLevelClient(builder);
        return client;
    }
}

@Repository
public interface ItemRepository extends ElasticsearchRepository<Item, String> {
    // 定义你的方法
}

@RestController
public class ItemController {

    @Autowired
    private ItemRepository itemRepository;

    @GetMapping("/items")
    public ResponseEntity<List<Item>> getItems() {
        Iterable<Item> items = itemRepository.findAll();
        List<Item> itemList = new ArrayList<>();
        items.forEach(itemList::add);
        return ResponseEntity.ok(itemList);
    }
}

elasticsearch.host=localhost
elasticsearch.port=9200