Elasticsearch8.1-ElasticsearchClient-Java客户端简单增删查改-随笔

• 环境准备
  1. Springboot 基本环境
     • 自行前往https://start.spring.io/ 构建一个即可
  2. Elasticsearch服务端
     • 简单说下windows版本的安装  https://www.elastic.co/cn/downloads/elasticsearch   下载最新版8.1.0，之后解压 不要放到中文目录下，进入bin目录双击运行elasticsearch.bat.
• 相关依赖

  1. pom.xml   ELasticsearch相关的依赖

     <dependency>
         <groupId>co.elastic.clients</groupId>
         <artifactId>elasticsearch-java</artifactId>
         <version>8.1.0</version>
     </dependency>
     <dependency>
         <groupId>com.fasterxml.jackson.core</groupId>
         <artifactId>jackson-databind</artifactId>
         <version>2.13.2</version>
     </dependency>

  2. application.yml

     elasticsearch:
       host: 127.0.0.1
       port: 9200

 

---

具体实现

首先要建立连接，这样就能在后续使用springboot自动装配

@Autowired
private ElasticsearchClient elasticsearchClient;

具体代码如下

查看代码

package cn.daimao.TestTryProject.bean;

import co.elastic.clients.elasticsearch.ElasticsearchClient;
import co.elastic.clients.json.jackson.JacksonJsonpMapper;
import co.elastic.clients.transport.ElasticsearchTransport;
import co.elastic.clients.transport.rest_client.RestClientTransport;
import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;

@Component
public class ElasticClient {
    @Value("${elasticsearch.host}")
    private String host;
    @Value("${elasticsearch.port}")
    private Integer port;

    @Bean
    public ElasticsearchClient getClient() {
        RestClientBuilder builder = RestClient.builder(
                new HttpHost(host, port));
        ElasticsearchTransport transport = new RestClientTransport(builder.build(), new JacksonJsonpMapper());
        return new ElasticsearchClient(transport);
    }
}

创建索引

@Autowired
private ElasticsearchClient elasticsearchClient;
@PostMapping("/createIndex")
public ResultJson createIndex(@RequestParam String indexName) throws IOException {
    elasticsearchClient.indices().create(createIndex -> createIndex.index(indexName));
    return ResultJson.success();
}

上传文档（数据）到索引

.index() 指定索引

.id() 设置该文档的id 如果不设置则会自动生成

.document() 具体的对象

我这里用的TProduct 更换成自己需要检索的分词结构即可。

返回ResultJson 只是一个通用类不重要。

查看代码

    public ResultJson uploadProduct(TProduct tProduct)  {
        IndexRequest<TProduct> req ;
        req = IndexRequest.of( b->
                b.index("product").id(tProduct.getProductId()+"").document(tProduct));
        try {
            elasticsearchClient.index(req);
            return ResultJson.success();
        } catch (IOException e) {
            return ResultJson.failure(e.toString());
        }
    }

修改指定索引的对应ID的文档内容

.index() 指定索引

.id() 要修改的文档的id，我上面上传是用的TProduct对象的productId,所以这里也用这个属性来更新

.doc() 修改后的对象

    public ResultJson updateDocument(TProduct tProduct){
        UpdateRequest<TProduct,TProduct> req;
        req = UpdateRequest.of(
                b-> b.index("product").id(tProduct.getProductId()+"")
                                .doc(tProduct)
        );
        try {
            elasticsearchClient.update(req,TProduct.class);
            return ResultJson.success();
        } catch (IOException e) {
            return ResultJson.failure(e.toString());
        }
    }

删除指定索引的文档

.index() 指定索引

.id() 要删除的文档的id，我上面上传是用的TProduct对象的productId,所以这里也用这个属性来更新

查看代码

    public ResultJson deleteDocument(Long productId){
        DeleteRequest req ;
        req = DeleteRequest.of(
                b-> b.index("product").id(productId+"")
        );
        try {
            elasticsearchClient.delete(req);
            return ResultJson.success();
        } catch (IOException e) {
            return ResultJson.failure(e.toString());
        }
    }

查询

tProductList 存放最后查询hit到的结果集

调用客户端的search方法，目前只写了个matchQuery模糊查询，后面是拿到response的处理，官网复制粘贴的---复杂查询待补充

查看代码

public ResultJson queryTest(String name) throws IOException {
        List<TProduct> tProductList = new ArrayList<>();

        SearchResponse<TProduct> response = elasticsearchClient.search(
                s -> s.index("product")
                        .query(
                                q -> q.match(
                                        t -> t.field("productName")
                                                .query(name)
                                )

                        )
                ,
                TProduct.class

        );
        TotalHits total = response.hits().total();
        boolean isExactResult = total.relation() == TotalHitsRelation.Eq;
        if (isExactResult) {
            log.info("There are {} results", total.value());
        } else {
            log.info("There are more than {} results", total.value());
        }
        List<Hit<TProduct>> hits = response.hits().hits();
        for (Hit<TProduct> hit : hits) {
            TProduct product = hit.source();
            tProductList.add(product);
        }
        return ResultJson.success(tProductList);
    }