用springboot+es实现查询

以下是使用Spring Boot和Elasticsearch进行查询的步骤：

1. 在pom.xml文件中添加Elasticsearch的依赖：

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

2. 创建一个Elasticsearch配置类，并配置Elasticsearch的主机和端口：

@Configuration
@EnableElasticsearchRepositories(basePackages = "com.example.demo.repository")
public class ElasticsearchConfig {

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

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

    @Bean
    public RestHighLevelClient client() {
        RestClientBuilder builder = RestClient.builder(new HttpHost(host, port));
        RestHighLevelClient client = new RestHighLevelClient(builder);
        return client;
    }

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

3. 创建一个实体类，并使用@Document注解将其映射到Elasticsearch中的索引：

@Document(indexName = "books")
public class Book {

    @Id
    private String id;

    private String title;

    private String author;

    private String description;

    // getters and setters
}

4. 创建一个Repository接口，继承ElasticsearchRepository：

public interface BookRepository extends ElasticsearchRepository<Book, String> {

    List<Book> findByTitle(String title);
}

5. 在Controller中注入BookRepository，并使用它进行查询：

@RestController
@RequestMapping("/books")
public class BookController {

    @Autowired
    private BookRepository bookRepository;

    @GetMapping("/search")
    public List<Book> search(@RequestParam String title) {
        return bookRepository.findByTitle(title);
    }
}

这样就可以使用Spring Boot和Elasticsearch进行查询了。在浏览器中访问http://localhost:8080/books/search?title=xxx，即可返回与指定标题匹配的书籍列表。