Es的基础工具类，可以获取单例的RestHighLevelClient类和BulkProcessor类。

1. 引入依赖

        <!--解决：java.lang.NoClassDefFoundError: org/elasticsearch/common/xcontent/DeprecationHandler-->
        <!-- elasticsearch -->
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.5.1</version>
        </dependency>

        <!-- elasticsearch-rest-client -->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-client</artifactId>
            <version>7.5.1</version>
        </dependency>

        <!-- elasticsearch-rest-high-level-client -->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.5.1</version>
            <exclusions>
                <exclusion>
                    <groupId>org.elasticsearch.client</groupId>
                    <artifactId>elasticsearch-rest-client</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.elasticsearch</groupId>
                    <artifactId>elasticsearch</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

2. 工具类

@Slf4j
public class EsUtil {

    private static RestHighLevelClient restHighLevelClient;

    private static BulkProcessor bulkProcessor;

    static {
        List<HttpHost> httpHosts = new ArrayList<>();
        //填充数据
        httpHosts.add(new HttpHost("120.0.0.1", 9200));
        httpHosts.add(new HttpHost("120.0.0.1", 9201));
        httpHosts.add(new HttpHost("120.0.0.1", 9202));
        //填充host节点
        RestClientBuilder builder = RestClient.builder(httpHosts.toArray(new HttpHost[0]));

        builder.setRequestConfigCallback(requestConfigBuilder -> {
            requestConfigBuilder.setConnectTimeout(1000);
            requestConfigBuilder.setSocketTimeout(1000);
            requestConfigBuilder.setConnectionRequestTimeout(1000);
            return requestConfigBuilder;
        });

        //填充用户名密码
        final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials("username", "password"));

        builder.setHttpClientConfigCallback(httpClientBuilder -> {
            httpClientBuilder.setMaxConnTotal(30);
            httpClientBuilder.setMaxConnPerRoute(30);
            httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
            return httpClientBuilder;
        });

        restHighLevelClient = new RestHighLevelClient(builder);
    }

    static {
        bulkProcessor=createBulkProcessor();
    }

    private static BulkProcessor createBulkProcessor() {

        BulkProcessor.Listener listener = new BulkProcessor.Listener() {
            @Override
            public void beforeBulk(long executionId, BulkRequest request) {
                log.info("1. 【beforeBulk】批次[{}] 携带 {} 请求数量", executionId, request.numberOfActions());
            }

            @Override
            public void afterBulk(long executionId, BulkRequest request,
                                  BulkResponse response) {
                if (!response.hasFailures()) {
                    log.info("2. 【afterBulk-成功】批量 [{}] 完成在 {} ms", executionId, response.getTook().getMillis());
                } else {
                    BulkItemResponse[] items = response.getItems();
                    for (BulkItemResponse item : items) {
                        if (item.isFailed()) {
                            log.info("2. 【afterBulk-失败】批量 [{}] 出现异常的原因 : {}", executionId, item.getFailureMessage());
                            break;
                        }
                    }
                }
            }

            @Override
            public void afterBulk(long executionId, BulkRequest request,
                                  Throwable failure) {

                List<DocWriteRequest<?>> requests = request.requests();
                List<String> esIds = requests.stream().map(DocWriteRequest::id).collect(Collectors.toList());
                log.error("3. 【afterBulk-failure失败】es执行bluk失败,失败的esId为：{}", esIds, failure);
            }
        };

        BulkProcessor.Builder builder = BulkProcessor.builder(((bulkRequest, bulkResponseActionListener) -> {
            restHighLevelClient.bulkAsync(bulkRequest, RequestOptions.DEFAULT, bulkResponseActionListener);
        }), listener);

        builder.setBulkActions(10000);
        builder.setBulkSize(new ByteSizeValue(8L, ByteSizeUnit.MB));
        //设置允许执行的并发请求数。
        builder.setConcurrentRequests(8);
        builder.setFlushInterval(TimeValue.timeValueSeconds(1));
        //设置重试策略
        builder.setBackoffPolicy(BackoffPolicy.constantBackoff(TimeValue.timeValueSeconds(1), 3));
        return builder.build();
    }


    public static RestHighLevelClient getRestHighLevelClient() {
        return restHighLevelClient;
    }

    public static BulkProcessor getBulkProcessor() {
        return bulkProcessor;
    }

    //远程调用
    public static List<SearchHit> remoteSearch(SearchRequest searchRequest, SearchSourceBuilder searchSourceBuilder) throws IOException {
        List<SearchHit> results = new ArrayList<>();
        searchRequest.indices("test_demo");
        searchRequest.source(searchSourceBuilder);
        log.info("dsl:" + searchSourceBuilder.toString());
        SearchResponse response = EsUtil.getRestHighLevelClient().search(searchRequest, RequestOptions.DEFAULT);

        SearchHits hits = response.getHits();
        Iterator<SearchHit> iterator = hits.iterator();
        while (iterator.hasNext()) {
            SearchHit next = iterator.next();
            log.info("输出分数:" + next.getScore());
            log.info("输出数据:" + next.getSourceAsString());
            results.add(next);
        }
        return results;
    }
}