利用JavaRestClient实现创建、删除索引库，判断索引库是否存在_resthighlevelclient 删除索引

1、初始化RestClient

在elasticsearch提供的API中，与elasticsearch一切交互都封装在一个名为RestHighLevelClient的类中，必须先完成这个对象的初始化，建立与elasticsearch的连接。

1）引入es的RestHighLevelClient依赖：

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

注：导入的依赖的版本要和打开的es的版本对应

 2）初始化RestHighLevelClient：

//初始化RestHighLevelClient：  
RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(HttpHost.create("http://192.168.177.132:9200"))
        );
    }

 2、创建索引库

        //初始化RestHighLevelClient：
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(HttpHost.create("http://192.168.177.132:9200"))
        );
        //创建请求
        CreateIndexRequest request = new CreateIndexRequest("hotel");
        //设置参数
        //HotelConstants.HOTEL_MAPPING：是封装了的json建库语句
        request.source(HotelConstants.HOTEL_MAPPING, XContentType.JSON);
        //执行请求
        client.indices().create(request, RequestOptions.DEFAULT);
 
        System.out.println("索引库创建完毕");

 把建库的json封装

package cn.itcast.hotel.utils;
 
/**
 * @author ning
 * @since 2022/12/4 22:08
 */
 
public class HotelConstants {
    public static final String HOTEL_MAPPING ="{\n" +
            "  \"mappings\": {\n" +
            "    \"properties\": {\n" +
            "      \"id\": {\n" +
            "        \"type\": \"keyword\"\n" +
            "      },\n" +
            "      \"name\":{\n" +
            "        \"type\": \"text\",\n" +
            "        \"analyzer\": \"ik_max_word\",\n" +
            "        \"copy_to\": \"all\"\n" +
            "      },\n" +
            "      \"address\":{\n" +
            "        \"type\": \"keyword\",\n" +
            "        \"index\": false\n" +
            "      },\n" +
            "      \"price\":{\n" +
            "        \"type\": \"integer\"\n" +
            "      },\n" +
            "      \"score\":{\n" +
            "        \"type\": \"integer\"\n" +
            "      },\n" +
            "      \"brand\":{\n" +
            "        \"type\": \"keyword\",\n" +
            "        \"copy_to\": \"all\"\n" +
            "      },\n" +
            "      \"city\":{\n" +
            "        \"type\": \"keyword\"\n" +
            "      },\n" +
            "      \"starName\":{\n" +
            "        \"type\": \"keyword\"\n" +
            "      },\n" +
            "      \"business\":{\n" +
            "        \"type\": \"keyword\",\n" +
            "        \"copy_to\": \"all\"\n" +
            "      },\n" +
            "      \"location\":{\n" +
            "        \"type\": \"geo_point\"\n" +
            "      },\n" +
            "      \"pic\":{\n" +
            "        \"type\": \"keyword\",\n" +
            "        \"index\": false\n" +
            "      },\n" +
            "      \"all\":{\n" +
            "        \"type\": \"text\",\n" +
            "        \"analyzer\": \"ik_max_word\"\n" +
            "      }\n" +
            "    }\n" +
            "  }\n" +
            "}";
}

 3、删除索引库

        //初始化RestHighLevelClient：
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(HttpHost.create("http://192.168.177.132:9200"))
        );
        //创建请求
        DeleteIndexRequest request = new DeleteIndexRequest("hotel");
        //执行请求
        client.indices().delete(request,RequestOptions.DEFAULT);
 
        System.out.println("索引库删除完毕");
    }

 4、判断索引库是否存在

        //初始化RestHighLevelClient：
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(HttpHost.create("http://192.168.177.132:9200"))
        );
        //创建请求
        GetIndexRequest request = new GetIndexRequest("hotel");
        //执行请求
        boolean exists = client.indices().exists(request, RequestOptions.DEFAULT);
 
        System.out.println("索引库是否存在？" + exists);