Elasticsearch—(MacOs)

1⃣️环境准备

1. 准备 Java 环境：终端输入 java -version 命令来确认版本是否符合 Elasticsearch 要求
2. 下载并解压 Elasticsearch：前往（https://www.elastic.co/downloads/elasticsearch）选择适合你的 Mac 系统的 Elasticsearch 版本进行下载
3. 设置 Elasticsearch 配置：在 config 目录下找到并打开 elasticsearch.yml 配置文件。根据你的需求，修改其中的一些设置，比如监听的端口、集群名称等
4. 启动 Elasticsearch：打开终端，进入 Elasticsearch 解压目录，执行以下命令启动 Elasticsearch：

   ./bin/elasticsearch
   

5. 验证 Elasticsearch 是否正常运行：打开浏览器，访问 http://localhost:9200 地址，如果能看到返回的 JSON 格式的信息，说明 Elasticsearch 已经成功安装并运行。

🌟使用步骤

1. 配置依赖：在项目的构建文件（例如Maven的pom.xml）中添加Elasticsearch相关的依赖。这通常包括Spring Data Elasticsearch和Elasticsearch的Java客户端依赖。
2. 配置Elasticsearch连接信息：在Spring的配置文件中，配置Elasticsearch连接的一些必要信息，例如主机名、端口号等。这些信息将用于与Elasticsearch建立连接。
3. 创建Elasticsearch实体类：在Java中创建实体类，可以使用注解标注字段与Elasticsearch中的文档属性的映射关系。这些实体类通常使用JPA或Spring Data Elasticsearch提供的注解来简化与Elasticsearch的数据交互。
4. 编写Elasticsearch相关的数据访问接口：使用Spring Data Elasticsearch提供的Repository接口，定义与Elasticsearch进行数据交互的查询方法。可以通过方法命名规则或自定义查询语句实现各种查询操作。
5. 注入Elasticsearch的Repository：在需要使用Elasticsearch的地方，通过依赖注入方式获取到Elasticsearch的Repository。可以在Service层或Controller层中使用该Repository来进行查询、保存、更新等操作。
6. 执行Elasticsearch操作：通过调用Elasticsearch的Repository方法，执行对Elasticsearch的数据操作。可以执行各种查询，例如基于关键字的全文搜索、聚合操作等。

2⃣️使用

要使用Elasticsearch进行增删改查等操作，你可以通过Postman来实现。下面我将提供一个使用RESTful API来演示的示例：

💫创建索引库

💫添加文档(添加行)

💫查询索引库

💫修改索引库

💫删除索引库

 3⃣️与Java使用

如何使用Java与Elasticsearch进行索引的创建、文档的增加、查询、修改和删除操作：

💠添加Elasticsearch Maven依赖：

在pom.xml文件中添加以下依赖项：

<dependencies>
    <dependency>
        <groupId>org.elasticsearch.client</groupId>
        <artifactId>elasticsearch-rest-high-level-client</artifactId>
        <version>7.13.3</version>
    </dependency>
    <dependency>
        <groupId>org.elasticsearch.client</groupId>
        <artifactId>elasticsearch-rest-client</artifactId>
        <version>7.13.3</version>
    </dependency>
</dependencies>

💠创建索引库：

import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.indices.CreateIndexRequest;
import org.elasticsearch.client.indices.CreateIndexResponse;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.common.xcontent.json.JsonXContent;
 
// 创建RestHighLevelClient客户端
RestHighLevelClient client = new RestHighLevelClient(
        RestClient.builder("localhost:9200"));
 
// 创建索引请求
CreateIndexRequest request = new CreateIndexRequest("my_index");
request.settings(Settings.builder()
        .put("index.number_of_shards", 1)
        .put("index.number_of_replicas", 0));
 
// 创建映射
XContentBuilder mapping = JsonXContent.contentBuilder()
        .startObject()
        .startObject("properties")
        .startObject("user")
        .field("type", "keyword")
        .endObject()
        .startObject("postDate")
        .field("type", "date")
        .endObject()
        .startObject("message")
        .field("type", "text")
        .endObject()
        .endObject()
        .endObject();
request.mapping(mapping);
 
// 执行创建索引请求
CreateIndexResponse response = client.indices().create(request, RequestOptions.DEFAULT);
if (response.isAcknowledged()) {
    System.out.println("索引创建成功");
} else {
    System.out.println("索引创建失败");
}
 
// 关闭客户端
client.close();

💠添加文档：

import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.client.RestClient;
 
// 创建RestHighLevelClient客户端
RestHighLevelClient client = new RestHighLevelClient(
        RestClient.builder("localhost:9200"));
 
// 构建索引请求
IndexRequest request = new IndexRequest("my_index");
request.id("1");
String jsonString = "{" +
                      "\"user\":\"John\"," +
                      "\"postDate\":\"2023-09-25\"," +
                      "\"message\":\"This is a sample document\"" +
                    "}";
request.source(jsonString, XContentType.JSON);
 
// 执行索引请求
IndexResponse response = client.index(request, RequestOptions.DEFAULT);
 
// 获取响应结果
String index = response.getIndex();
String id = response.getId();
if (response.getResult() == DocWriteResponse.Result.CREATED) {
    System.out.println("文档创建成功，索引：" + index + "，id：" + id);
} else if (response.getResult() == DocWriteResponse.Result.UPDATED) {
    System.out.println("文档更新成功，索引：" + index + "，id：" + id);
}
 
// 关闭客户端
client.close();

💠查询索引库

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.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.client.RestClient;
 
// 创建RestHighLevelClient客户端
RestHighLevelClient client = new RestHighLevelClient(
        RestClient.builder("localhost:9200"));
 
// 构建搜索请求
SearchRequest request = new SearchRequest("my_index");
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.matchQuery("message", "sample"));
request.source(searchSourceBuilder);
 
// 执行搜索请求
SearchResponse response = client.search(request, RequestOptions.DEFAULT);
 
// 处理搜索结果
SearchHits hits = response.getHits();
for (SearchHit hit : hits.getHits()) {
    String sourceAsString = hit.getSourceAsString();
    System.out.println(sourceAsString);
}
 
// 关闭客户端
client.close();

💠修改索引库：

import org.elasticsearch.action.update.UpdateRequest;
import org.elasticsearch.action.update.UpdateResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.client.RestClient;
 
// 创建RestHighLevelClient客户端
RestHighLevelClient client = new RestHighLevelClient(
        RestClient.builder("localhost:9200"));
 
// 构建更新请求
UpdateRequest request = new UpdateRequest("my_index", "1")
        .doc(XContentFactory.jsonBuilder()
                .startObject()
                .field("message", "Updated document")
                .endObject());
 
// 执行更新请求
UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
String index = response.getIndex();
String id = response.getId();
if (response.getResult() == DocWriteResponse.Result.UPDATED) {
    System.out.println("文档更新成功，索引：" + index + "，id：" + id);
} else if (response.getResult() == DocWriteResponse.Result.NOOP) {
    System.out.println("文档未发生更新，索引：" + index + "，id：" + id);
}
 
// 关闭客户端
client.close();

💠删除索引库：

import org.elasticsearch.action.delete.DeleteRequest;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.RestClient;
 
// 创建RestHighLevelClient客户端
RestHighLevelClient client = new RestHighLevelClient(
        RestClient.builder("localhost:9200"));
 
// 构建删除请求
DeleteRequest request = new DeleteRequest("my_index", "1");
 
// 执行删除请求
DeleteResponse response = client.delete(request, RequestOptions.DEFAULT);
String index = response.getIndex();
String id = response.getId();
if (response.getResult() == DocWriteResponse.Result.DELETED) {
    System.out.println("文档删除成功，索引：" + index + "，id：" + id);
} else if (response.getResult() == DocWriteResponse.Result.NOT_FOUND) {
    System.out.println("文档未找到，索引：" + index + "，id：" + id);
}
 
// 关闭客户端
client.close();