【elastic search】JAVA操作elastic search

柔情只为你懂 2024-02-05 23:26 99阅读 0赞

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**目录**

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][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][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：

1.  拼json
2.  创建request
3.  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：

![eda8ac591b414b55ad34c8476505d060.png][]

**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：

![79bdb655bb184d8aba007184d645606d.png][]

**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);
        }
    
    }

[2fcdbbddddb047a09689849dbbd6fba2.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/852727a9b99848ff81059009d4c84936.png
[176087953ff9473c9f15625687d42437.gif]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/518f5c996fb54bff8162df951e2660be.png
[https_bugman.blog.csdn.net_article_details_135342256_spm_1001.2014.3001.5502]: https://bugman.blog.csdn.net/article/details/135342256?spm=1001.2014.3001.5502
[eda8ac591b414b55ad34c8476505d060.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/da64140a5c7340a3b775a0c7f4c8aac5.png
[79bdb655bb184d8aba007184d645606d.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/eb1658cdf9a543f683fbf859f3b71bf4.png