文章目录

• 前言
• 一、引入依赖
• 二、配置连接
• • 1.直接配置连接
  • 2.从旧版High Level Rest Client迁移值新版
• 2.Lambda表达式相关api的使用
• • • 创建索引
    • 写入单个文档
    • 批量插入
    • 通过id查找文档
  • 搜索文档
  • • 聚合文档
• 总结

前言

elasaticsearch新版java客户端详细教程，支持响应式编程，Lambda表达式。兼容旧版High Level Rest Client。网上相关教程少，我在这里出一个。elasaticsearch相关安装这里不介绍了

一、引入依赖

 <dependency>     <groupId>co.elastic.clients</groupId>     <artifactId>elasticsearch-java</artifactId>     <version>8.2.2</version> </dependency> <dependency>     <groupId>com.fasterxml.jackson.core</groupId>     <artifactId>jackson-databind</artifactId>     <version>2.12.3</version> </dependency> <dependency>     <groupId>jakarta.json</groupId>     <artifactId>jakarta.json-api</artifactId>     <version>2.0.1</version> </dependency>

二、配置连接

有几种方式，这里介绍两种，如果不考虑之前旧版High Level Rest Client的客户端采用第一种就行

1.直接配置连接

//同步客户端    public ElasticsearchClient elasticsearchClient(){ ElasticsearchTransport transport = getElasticsearchTransport();// And create the API client ElasticsearchClient client = new ElasticsearchClient(transport); return client;    }    //elasticsearch异步客户端    public ElasticsearchAsyncClient elasticsearchAsyncClient (){ ElasticsearchTransport transport = getElasticsearchTransport();// And create the API client ElasticsearchAsyncClient client = new ElasticsearchAsyncClient(transport); return client;    }//ElasticsearchTransport用于创建客户端    public ElasticsearchTransport getElasticsearchTransport(){ CredentialsProvider credentialsProvider =  new BasicCredentialsProvider(); credentialsProvider.setCredentials(AuthScope.ANY,  new UsernamePasswordCredentials(username, password));//配置用户名密码 // Create the low-level client RestClient restClient = RestClient.builder(   new HttpHost(host, port)) //配置路径 端口  .setHttpClientConfigCallback(httpAsyncClientBuilder ->   httpAsyncClientBuilder.setDefaultCredentialsProvider(credentialsProvider))  .build();// Create the transport with a Jackson mapper ElasticsearchTransport transport = new RestClientTransport(  restClient, new JacksonJsonpMapper()); return transport;    }

阻塞和异步客户端
API 客户端有两种形式：阻塞和异步。异步客户端上的所有方法都返回一个标准CompletableFuture.
根据需要，两种风格可以同时使用，共享相同的传输对象。我们这里就介绍同步客户端的使用。

2.从旧版High Level Rest Client迁移值新版

两种客户端可以同时存在，自行选择使用

// 低级客户端RestClient httpClient = RestClient.builder(    new HttpHost("localhost", 9200)).build();//创建旧版旧版High Level Rest ClientRestHighLevelClient hlrc = new RestHighLevelClientBuilder(httpClient)    .setApiCompatibilityMode(true)     .build();// 创建新版ElasticsearchClient ElasticsearchTransport transport = new RestClientTransport(    httpClient,    new JacksonJsonpMapper());ElasticsearchClient esClient = new ElasticsearchClient(transport);

2.Lambda表达式相关api的使用

创建索引

    @Test    public void createIndex() throws IOException { ElasticsearchClient client = getElasticsearchClient(); System.out.println("连接成功--------------------------"); CreateIndexResponse createIndexResponse = client.indices().create(  index ->   index.index("productlist").aliases("product" , aliase ->    aliase.isWriteIndex(true)) ); System.out.println(createIndexResponse.toString());    }

写入单个文档

实体类

public class Product implements Serializable {    private static final long serialVersionUID = 1L;    private String no;    private String name;    private String createBy;    public Product() {    }    public Product(String no, String name, String createBy) { this.no = no; this.name = name; this.createBy = createBy;    }    public String getNo() { return no;    }    public void setNo(String no) { this.no = no;    }    public String getName() { return name;    }    public void setName(String name) { this.name = name;    }    public String getCreateBy() { return createBy;    }    public void setCreateBy(String createBy) { this.createBy = createBy;    }    @Override    public String toString() { return "Product{" +  "no='" + no + '\'' +  ", name='" + name + '\'' +  ", createBy='" + createBy + '\'' +  '}';    }}

Product product = new Product("bk-1", "City bike", 123.0);IndexResponse response = esClient.index(i -> i    .index("products")    .id(product.getSku())    .document(product));

批量插入

 @Test    public void bulkInsertDocument() throws IOException { ElasticsearchClient client = getElasticsearchClient(); System.out.println("连接成功--------------------------"); List<Product> products = new ArrayList<>(); products.add(new Product("asdad","dasdasd","adasdasdad")); products.add(new Product("12313","453","sfsdfdsfdsf")); BulkRequest.Builder br = new BulkRequest.Builder(); for (Product product : products) {     br.operations(      op -> op.index(index -> index.index("productlist").document(product))     ); } BulkResponse bulk = client.bulk(br.build()); System.out.println(bulk);    }

通过id查找文档

    @Test    public void getOne() throws IOException { ElasticsearchClient client = getElasticsearchClient(); System.out.println("连接成功--------------------------"); GetResponse<Product> response = client.get(g -> g   .index("productlist")   .id("7ROTUIEBMxTIVL_J85rw"),  Product.class ); System.out.println(response.source());    }

搜索文档

String searchText = "bike";SearchResponse<Product> response = esClient.search(s -> s    .index("productlist")     .query(q -> q.match(t -> t .field("name").query(searchText) )    ),    Product.class      );TotalHits total = response.hits().total();boolean isExactResult = total.relation() == TotalHitsRelation.Eq;if (isExactResult) {    logger.info("There are " + total.value() + " results");} else {    logger.info("There are more than " + total.value() + " results");}List<Hit<Product>> hits = response.hits().hits();for (Hit<Product> hit: hits) {    Product product = hit.source();    logger.info("Found product " + product.getSku() + ", score " + hit.score());}

聚合文档

String searchText = "bike";Query query = MatchQuery.of(m -> m    .field("name")    .query(searchText))._toQuery();SearchResponse<Void> response = esClient.search(b -> b    .index("products")    .size(0)     .query(query)     .aggregations("price-histogram", a -> a  .histogram(h -> h      .field("price")     .interval(50.0) )    ),    Void.class );

总结

以上就是这篇要讲的内容，更多详细用法参考官网文档https://www.elastic.co/guide/en/elasticsearch/client/java-api-client/current/index.html