在这里找到答案：enter link description here

更新了工作正常的代码：

import java.io.IOException;

import javax.ws.rs.POST;
import javax.ws.rs.Path;

import org.apache.http.HttpHost;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.rest.RestStatus;

@Path("/elasticsearch")
public class ElasticSearchService {
    private static final String ELASTIC_SEARCH_USER_NAME = <my elastic search username>;
    private static final String ELASTIC_SEARCH_PASSWORD = <my elastic search password>;
    private static final String ELASTIC_SEARCH_ENDPOINT_URL = <my elastic search endpoint url>
    private static final Integer ELASTIC_SEARCH_PORT = 9243;

    @POST
    public void createElasticIndex() throws IOException {

        final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        credentialsProvider.setCredentials(AuthScope.ANY,
                new UsernamePasswordCredentials(ELASTIC_SEARCH_USER_NAME, ELASTIC_SEARCH_PASSWORD));

        RestClientBuilder builder = RestClient
                .builder(new HttpHost(
                        ELASTIC_SEARCH_ENDPOINT_URL,
                        ELASTIC_SEARCH_PORT, "https"))
                .setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
                    @Override
                    public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
                        return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
                    }
                });

        RestHighLevelClient client = new RestHighLevelClient(builder);

        IndexRequest request = new IndexRequest(
                "contacts",
                "doc",
                "1");
        String jsonString = "{" +
                ""user":"frank"," +
                ""postDate":"2020-03-02"," +
                ""message":"created this document from Java"" +
                "}";
        request.source(jsonString, XContentType.JSON);

        try {
            IndexResponse response = client.index(request, RequestOptions.DEFAULT);
            System.out.println(response);

        } catch (ElasticsearchException e) {
            if (e.status() == RestStatus.CONFLICT) {
            }
        }

        client.close();
    }

}

此代码创建一个名为contacts的索引，并向该索引添加一个文档。

您可以使用ElasticSearch的同步和异步API来创建索引。但这取决于需求。

找到下面的ElasticSearch文档链接，这些文档解释了同步和异步API的使用。https://www.elastic.co/guide/en/elasticsearch/client/java-rest/master/java-rest-high-create-index.html

示例代码：-Synchronous API：-

CreateIndexRequest request = new CreateIndexRequest("twitter");
    request.settings(Settings.builder() 
        .put("index.number_of_shards", 3)
        .put("index.number_of_replicas", 2)
    );

CreateIndexResponse createIndexResponse = client.indices().create(request, RequestOptions.DEFAULT);

异步接口：-

client.indices().createAsync(request, RequestOptions.DEFAULT, listener);

异步API增加了线程的优势，使API能够更好地工作。在异步API中，需要关注的是接收响应。以下是如何才能收到回复的片段。

PlainActionFuture<CreateIndexResponse > future = new PlainActionFuture<>();
client.indices().createAsync(request, RequestOptions.DEFAULT, future);
CreateIndexResponse response = future.actionGet();

如果您知道如何通过API插入文档，那么这种方式将使您更容易执行任何类似的API操作(删除、发布、放置...)首先，您将需要RestHighLevelClient以及您需要做的所有工作

String index = "/indexName/_doc";
Request request = new Request("POST", index);
request.setJsonEntity(
      "{ "message": " example add insert" }"
);

client.getLowLevelClient().performRequest(request);

这将像API一样执行。