【中间件】使用ElasticSearch提供的RestClientAPI操作ES

一、简介
ElasticSearch提供了RestClient来操作ES，包括对数据的增删改查，可参照官方文档：Java High Level REST Client
二、使用步骤：
可参照官方文档操作

1. 导包

<dependency><groupId>org.elasticsearch.client</groupId><artifactId>elasticsearch-rest-high-level-client</artifactId><version>7.16.2</version></dependency></dependencies>

2. 写配置
   官方文档Initialization中配置如下，指明了要操作的ES所在的服务器地址和端口号

RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(new HttpHost("localhost", 9200, "http"),new HttpHost("localhost", 9201, "http")));

由于我们经常用到该对象，如果每次都写一遍的话会很麻烦，代码冗余，因此我们可一在配置类中创建好该bean，并将其放到容器中，要使用时，用@Autowried自动注入就行，具体配置如下：

@Configuration
public class EsConfig {public static final RequestOptions COMMON_OPTIONS;static {RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
//        builder.addHeader("Authorization", "Bearer " + TOKEN);
//        builder.setHttpAsyncResponseConsumerFactory(
//                new HttpAsyncResponseConsumerFactory
//                        .HeapBufferedResponseConsumerFactory(30 * 1024 * 1024 * 1024));COMMON_OPTIONS = builder.build();}@Beanpublic RestHighLevelClient restHighLevelClient(){RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(new HttpHost("192.168.195.131", 9200, "http")));return client;}
}

3. 业务使用
   例如，将数据批量保存至ES中，RestHighLevelClient中提供了所有对ES进行操作的方法：

@Slf4j
@Service
public class ProductSaveServiceImpl implements ProductSaveService {@AutowiredRestHighLevelClient restHighLevelClient;@Overridepublic boolean productStatusUp(List<SkuEsModel> skuEsModels) throws IOException {// 1、在es中建立一个索引，建立好映射关系--在es中执行put product即可// 2、保存数据到es   BulkRequest bulkRequest, RequestOptions optionsBulkRequest bulkRequest = new BulkRequest();skuEsModels.forEach(skuEsModel -> {IndexRequest indexRequest = new IndexRequest(EsConstant.PRODUCT_INDEX);indexRequest.id(skuEsModel.getSkuId().toString());indexRequest.source(JSON.toJSONString(skuEsModel), XContentType.JSON);bulkRequest.add(indexRequest);});BulkResponse bulk = restHighLevelClient.bulk(bulkRequest, EsConfig.COMMON_OPTIONS);// 处理上架错误,记录到日志List<String> errors = Arrays.stream(bulk.getItems()).map(BulkItemResponse::getId).collect(Collectors.toList());log.info("商品上架完成：{}", errors);return bulk.hasFailures();}
}