【elastic search】JAVA操作elastic search-编程知识

1.环境准备

2.ES JAVA API

3.Spring Boot操作ES

1.环境准备

本文是作者ES系列的第三篇文章，关于ES的核心概念移步：

https://bugman.blog.csdn.net/article/details/135342256?spm=1001.2014.3001.5502

关于ES的下载安装教程以及基本使用，移步：

https://bugman.blog.csdn.net/article/details/135342256?spm=1001.2014.3001.5502

在前文中，我们已经搭建好了一个es+kibana的基础环境，本文将继续使用该环境，演示JAVA操作es。

2.ES JAVA API

Elasticsearch Rest High Level Client 是 Elasticsearch 官方提供的一个 Java 客户端库，用于与 Elasticsearch 进行交互。这个客户端库是基于 REST 风格的 HTTP 协议，与 Elasticsearch 进行通信，提供了更高级别的抽象，使得开发者可以更方便地使用 Java 代码与 Elasticsearch 进行交互。

依赖：

<dependency><groupId>org.elasticsearch</groupId><artifactId>elasticsearch</artifactId><version>7.17.3</version>
</dependency>
<dependency><groupId>org.elasticsearch.client</groupId><artifactId>elasticsearch-rest-high-level-client</artifactId><version>7.17.3</version>
</dependency>
<dependency><groupId>org.apache.logging.log4j</groupId><artifactId>log4j-core</artifactId><version>2.10.0</version>
</dependency>
<dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version>
</dependency>
<dependency><groupId>com.alibaba.fastjson2</groupId><artifactId>fastjson2</artifactId><version>2.0.45</version>
</dependency>

其实Rest High Level Client的使用逻辑一共就分散步：

拼json
创建request
client执行request

创建client：

RestHighLevelClient restHighLevelClient = new RestHighLevelClient(RestClient.builder(new HttpHost("127.0.0.1",9200,"http")));

创建索引：

@Testpublic void createIndex() throws IOException {//1.拼json//settingsSettings.Builder settings = Settings.builder().put("number_of_shards", 3).put("number_of_replicas", 1);//mappingsXContentBuilder mappings = JsonXContent.contentBuilder().startObject().startObject("properties").startObject("name").field("type", "text").endObject().startObject("age").field("type", "integer").endObject().endObject().endObject();//2.创建requestCreateIndexRequest createIndexRequest = new CreateIndexRequest("person").settings(settings).mapping(mappings);//3.client执行requestrestHighLevelClient.indices().create(createIndexRequest, RequestOptions.DEFAULT);}

创建文档：

@Testpublic void createDoc() throws IOException {Person person=new Person("1","zou",20);JSONObject json = JSONObject.from(person);System.out.println(json);IndexRequest request=new IndexRequest("person",null,person.getId().toString());request.source(json, XContentType.JSON);IndexResponse response = restHighLevelClient.index(request, RequestOptions.DEFAULT);System.out.println(response);}

响应结果：

修改文档：

@Testpublic void updateDoc() throws IOException {HashMap<String, Object> doc = new HashMap();doc.put("name","张三");String docId="1";UpdateRequest request=new UpdateRequest("person",null,docId);UpdateResponse response = restHighLevelClient.update(request, RequestOptions.DEFAULT);System.out.println(response.getResult().toString());}

删除文档：

@Testpublic void deleteDoc() throws IOException {DeleteRequest request=new DeleteRequest("person",null,"1");DeleteResponse response = restHighLevelClient.delete(request, RequestOptions.DEFAULT);System.out.println(response.getResult().toString());}

响应结果：

搜索示例：

import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;import java.io.IOException;public class ElasticsearchSearchExample {public static void main(String[] args) {// 创建 RestHighLevelClient 实例，连接到 Elasticsearch 集群RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(new HttpHost("localhost", 9200, "http")));// 构建搜索请求SearchRequest searchRequest = new SearchRequest("your_index"); // 替换为实际的索引名称// 构建查询条件SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();searchSourceBuilder.query(QueryBuilders.matchAllQuery()); // 查询所有文档// 设置一些可选参数searchSourceBuilder.from(0); // 设置起始索引，默认为0searchSourceBuilder.size(10); // 设置返回结果的数量，默认为10searchSourceBuilder.timeout(new TimeValue(5000)); // 设置超时时间，默认为1分钟// 将查询条件设置到搜索请求中searchRequest.source(searchSourceBuilder);try {// 执行搜索请求SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);// 处理搜索响应System.out.println("Search took: " + searchResponse.getTook());// 获取搜索结果SearchHits hits = searchResponse.getHits();System.out.println("Total hits: " + hits.getTotalHits().value);// 遍历搜索结果for (SearchHit hit : hits.getHits()) {System.out.println("Document ID: " + hit.getId());System.out.println("Source: " + hit.getSourceAsString());}} catch (IOException e) {// 处理异常e.printStackTrace();} finally {try {// 关闭客户端连接client.close();} catch (IOException e) {// 处理关闭连接异常e.printStackTrace();}}}
}

请注意，上述示例中的 your_index 应该替换为你实际的 Elasticsearch 索引名称。这个示例使用了简单的 matchAllQuery，你可以根据实际需求构建更复杂的查询条件。在搜索响应中，你可以获取到搜索的结果以及相关的元数据。

3.Spring Boot操作ES

在 Spring Boot 中操作 Elasticsearch 通常使用 Spring Data Elasticsearch，以标准的JPA的模式来操作ES。

依赖：

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.6.x</version> 
</parent>

<dependencies>

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>


<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-elasticsearch</artifactId>
</dependency>


<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
application.properties配置：

spring.data.elasticsearch.cluster-nodes=localhost:9200

实体类：

import org.springframework.data.annotation.Id;
import org.springframework.data.elasticsearch.annotations.Document;
import org.springframework.data.elasticsearch.annotations.Field;
import org.springframework.data.elasticsearch.annotations.FieldType;import java.util.Date;@Document(indexName = "blogpost_index")
public class BlogPost {@Idprivate String id;@Field(type = FieldType.Text)private String title;@Field(type = FieldType.Text)private String content;@Field(type = FieldType.Keyword)private String author;@Field(type = FieldType.Date)private Date publishDate;// 构造函数、getter和setterpublic BlogPost() {}public BlogPost(String id, String title, String content, String author, Date publishDate) {this.id = id;this.title = title;this.content = content;this.author = author;this.publishDate = publishDate;}// 省略 getter 和 setter 方法
}

dao层：

import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;public interface BlogPostRepository extends ElasticsearchRepository<BlogPost, String> {// 你可以在这里定义自定义查询方法}

service层：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;
import java.util.Optional;@Service
public class BlogPostService {private final BlogPostRepository blogPostRepository;@Autowiredpublic BlogPostService(BlogPostRepository blogPostRepository) {this.blogPostRepository = blogPostRepository;}public BlogPost save(BlogPost blogPost) {return blogPostRepository.save(blogPost);}public Optional<BlogPost> findById(String id) {return blogPostRepository.findById(id);}public List<BlogPost> findAll() {return (List<BlogPost>) blogPostRepository.findAll();}public void deleteById(String id) {blogPostRepository.deleteById(id);}}