【SpringCloud学习笔记】Elasticsearch

在Spring Cloud中，Elasticsearch是一个常用的搜索和分析引擎，可以用来增强应用的搜索功能。以下是一个使用Spring Data Elasticsearch的简单示例：

1. 首先，在pom.xml中添加Spring Data Elasticsearch的依赖：

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

2. 配置Elasticsearch客户端，在application.properties或application.yml中设置Elasticsearch的基本信息：

spring.data.elasticsearch.cluster-name=elasticsearch
spring.data.elasticsearch.cluster-nodes=localhost:9300

3. 创建一个Elasticsearch实体：

import org.springframework.data.annotation.Id;
import org.springframework.data.elasticsearch.annotations.Document;
 
@Document(indexName = "sampleindex")
public class SampleEntity {
    @Id
    private String id;
    private String content;
 
    // Getters and Setters
}

4. 创建一个Elasticsearch仓库接口：

import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;
 
public interface SampleEntityRepository extends ElasticsearchRepository<SampleEntity, String> {
    // 自定义查询方法
}

5. 使用仓库进行操作：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
 
import java.util.List;
 
@Service
public class SampleService {
 
    @Autowired
    private SampleEntityRepository repository;
 
    public SampleEntity create(SampleEntity entity) {
        return repository.save(entity);
    }
 
    public List<SampleEntity> findAll() {
        return repository.findAll();
    }
 
    // 其他操作
}

6. 使用Elasticsearch进行搜索：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.elasticsearch.core.ElasticsearchTemplate;
import org.springframework.data.elasticsearch.core.query.NativeSearchQueryBuilder;
import org.springframework.stereotype.Service;
 
@Service
public class SearchService {
 
    @Autowired
    private ElasticsearchTemplate elasticsearchTemplate;
 
    public Page<SampleEntity> search(String query, int page, int size) {
        PageRequest pageRequest = PageRequest.of(page, size);
        NativeSearchQueryBuilder queryBuilder = new NativeSearchQueryBuilder()
                .withQuery(queryStringQuery(query))
                .withPageable(pageRequest);
 
        ret