【elastic search】JAVA操作elastic search

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：

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

创建文档：

@Test
    public 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：

@Test
    public 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：

@Test
    public 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0
        searchSourceBuilder.size(10); // 设置返回结果的数量，默认为10
        searchSourceBuilder.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 {

    @Id
    private 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setter

    public 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;

    @Autowired
    public 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);
    }

}