ES通过API操作索引库

1. 导入restClient依赖

  <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.12.1</version>
        </dependency>

---

2. 了解ES核心客户端API

核心区别对比

特性	RestHighLevelClient	RestClient
定位	高级客户端（封装常用操作，推荐使用）	底层HTTP客户端（更灵活，更复杂）
API风格	面向对象（如 IndexRequest, SearchRequest）	基于HTTP请求构建（如 Request, Response）
维护状态	官方已停止维护（ES 7.15+）	仍维护（但推荐迁移到新客户端）
依赖关系	基于 RestClient 实现	是 RestHighLevelClient 的底层依赖
适用场景	快速开发标准功能	需要自定义请求或访问未封装API

---

3. 将RestHighLevelClient注册成Bean

package com.example.demo.config;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class ElasticSearchConfig {
    public static final String HOST = "127.0.0.1"; // es地址
    public static final int PORT = 9200; // es端口

    /**
     * 创建RestClient对象
     * @return
     */
    @Bean
    public RestHighLevelClient restClient() {
        return new RestHighLevelClient(RestClient.builder(new HttpHost(HOST, PORT)));
    }
}

4. 创建索引库

创建包和类用于保存索引结构：constants.HotelConstants

package com.example.demo.constants;

public class HotelConstants {
    public static final String MAPPER_TEMPLATE_USER = "{\n" +
            "  \"mappings\": {\n" +
            "    \"properties\": {\n" +
            "      \"id\": {\n" +
            "        \"type\": \"keyword\",  \n" +
            "        \"doc_values\": true  \n" +
            "      },\n" +
            "      \"username\": {\n" +
            "        \"type\": \"text\",     \n" +
            "        \"analyzer\": \"ik_max_word\", \n" +
            "        \"fields\": {\n" +
            "          \"keyword\": {\n" +
            "            \"type\": \"keyword\"  \n" +
            "          }\n" +
            "        },\n" +
            "        \"copy_to\": \"combined_search\"  \n" +
            "      },\n" +
            "      \"password\": {\n" +
            "        \"type\": \"keyword\",  \n" +
            "        \"index\": false      \n" +
            "      },\n" +
            "      \"phone\": {\n" +
            "        \"type\": \"keyword\",  \n" +
            "        \"ignore_above\": 20  \n" +
            "      },\n" +
            "      \"create_time\": {\n" +
            "        \"type\": \"date\",\n" +
            "        \"format\": \"yyyy-MM-dd HH:mm:ss||epoch_millis\"  \n" +
            "      },\n" +
            "      \"update_time\": {\n" +
            "        \"type\": \"date\",\n" +
            "        \"format\": \"yyyy-MM-dd HH:mm:ss||epoch_millis\"\n" +
            "      },\n" +
            "      \"status\": {\n" +
            "        \"type\": \"integer\", \n" +
            "        \"null_value\": 1     \n" +
            "      },\n" +
            "      \"balance\": {\n" +
            "        \"type\": \"integer\",  \n" +
            "        \"null_value\": 0     \n" +
            "      },\n" +
            "      \"combined_search\": {  \n" +
            "        \"type\": \"text\",\n" +
            "        \"analyzer\": \"ik_smart\"\n" +
            "      }\n" +
            "    }\n" +
            "  },\n" +
            "  \"settings\": {\n" +
            "    \"number_of_shards\": 3,    \n" +
            "    \"number_of_replicas\": 1,  \n" +
            "    \"analysis\": {             \n" +
            "      \"analyzer\": {\n" +
            "        \"ik_smart\": {         \n" +
            "          \"type\": \"custom\",\n" +
            "          \"tokenizer\": \"ik_max_word\"\n" +
            "        }\n" +
            "      }\n" +
            "    }\n" +
            "  }\n" +
            "}";
}

---

 /**
     * 创建索引库
     */
    @Test
    public void createIndex() throws IOException {
        // 创建请求，指定索引库名称
        CreateIndexRequest request = new CreateIndexRequest("user");
        //执行与数据库相对于的映射JSON
        CreateIndexRequest source = request.source(HotelConstants.MAPPER_TEMPLATE_USER, XContentType.JSON);
        // 发送请求
        //RequestOptions.DEFAULT：默认请求
        client.indices().create(source, RequestOptions.DEFAULT);
    }

执行前先确定是否删除user索引库，客户端查询一下如果为空就是删除了

#
GET /user

#
DELETE /user

运行测试方法后再次查询

---

5. 判断索引库是否存在

    /**
     * 判断索引库是否存在
     * @throws IOException
     */
    @Test
    void testIndexExists() throws IOException {
        // 创建请求，指定索引库名称
        GetIndexRequest request = new GetIndexRequest("user");
        // 发送请求，判断索引库是否存在
        boolean exists = client.indices().exists(request, RequestOptions.DEFAULT);
        // 打印结果，true表示存在，false表示不存在
        System.out.println(exists);
    }

---

6. 删除索引库

    /**
     * 删除索引库
     * @throws IOException
     */
    @Test
    void testDeleteIndex() throws IOException {
        // 创建请求，指定索引库名称
        DeleteIndexRequest request = new DeleteIndexRequest("user");
        // 发送请求
        client.indices().delete(request, RequestOptions.DEFAULT);
    }