spring boot整合 es 7.9.0版本, 给出详细代码, 要求扩展性强

好的，下面是详细的代码，其中包含了Spring Boot和Elasticsearch 7.9.0版本的整合，实现了基本的CURD操作，并且具有扩展性：

1. 添加依赖

首先，在pom.xml中添加以下依赖：

<dependencies>
    <!-- Elasticsearch 7.9.0 -->
    <dependency>
        <groupId>org.elasticsearch</groupId>
        <artifactId>elasticsearch</artifactId>
        <version>7.9.0</version>
    </dependency>
    <dependency>
        <groupId>org.elasticsearch.client</groupId>
        <artifactId>elasticsearch-rest-high-level-client</artifactId>
        <version>7.9.0</version>
    </dependency>
    <dependency>
        <groupId>org.elasticsearch.client</groupId>
        <artifactId>elasticsearch-rest-client</artifactId>
        <version>7.9.0</version>
    </dependency>
    <!-- Spring Boot -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

2. 配置文件

在application.properties中配置Elasticsearch连接信息：

elasticsearch.host=127.0.0.1
elasticsearch.port=9200
elasticsearch.scheme=http

3. 编写配置类

创建一个Elasticsearch配置类，用于创建Elasticsearch客户端：

import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.elasticsearch.client.ClientConfiguration;
import org.springframework.data.elasticsearch.client.RestClients;
import org.springframework.data.elasticsearch.config.AbstractElasticsearchConfiguration;
import org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate;

@Configuration
public class ElasticsearchConfig extends AbstractElasticsearchConfiguration {

    @Value("${elasticsearch.host}")
    private String host;

    @Value("${elasticsearch.port}")
    private int port;

    @Value("${elasticsearch.scheme}")
    private String scheme;

    @Override
    @Bean
    public RestHighLevelClient elasticsearchClient() {
        final ClientConfiguration clientConfiguration = ClientConfiguration.builder()
                .connectedTo(host + ":" + port)
                .usingSsl("https".equals(scheme))
                .build();

        return RestClients.create(clientConfiguration).rest();
    }

    @Bean
    public ElasticsearchRestTemplate elasticsearchTemplate() {
        return new ElasticsearchRestTemplate(elasticsearchClient());
    }
}

4. 编写实体类

创建一个实体类，用于映射Elasticsearch中的文档：

import lombok.Data;
import org.springframework.data.annotation.Id;
import org.springframework.data.elasticsearch.annotations.Document;

@Data
@Document(indexName = "article")
public class Article {
    @Id
    private String id;
    private String title;
    private String content;
}

5. 编写DAO接口

创建一个DAO接口，继承自ElasticsearchRepository，用于操作Elasticsearch中的文档：

import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;

public interface ArticleDao extends ElasticsearchRepository<Article, String> {
}

6. 编写服务类

创建一个服务类，用于对Elasticsearch中的文档进行CURD操作：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.Optional;

@Service
public class ArticleService {

    @Autowired
    private ArticleDao articleDao;

    public void save(Article article) {
        articleDao.save(article);
    }

    public Optional<Article> findById(String id) {
        return articleDao.findById(id);
    }

    public void deleteById(String id) {
        articleDao.deleteById(id);
    }
}

7. 编写控制器

创建一个控制器，用于对Elasticsearch中的文档进行RESTful API操作：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.Optional;

@RestController
@RequestMapping("/article")
public class ArticleController {

    @Autowired
    private ArticleService articleService;

    @PostMapping
    public void save(@RequestBody Article article) {
        articleService.save(article);
    }

    @GetMapping("/{id}")
    public Optional<Article> findById(@PathVariable String id) {
        return articleService.findById(id);
    }

    @DeleteMapping("/{id}")
    public void deleteById(@PathVariable String id) {
        articleService.deleteById(id);
    }
}

这样，我们就实现了基本的Elasticsearch CURD操作，并且具有扩展性。我们可以根据需要，对DAO接口和服务类进行扩展，实现更加复杂的操作。