Elasticsearch java api操作（二）（Java High Level Rest Client）

一、说明：

　　一、Elasticsearch提供了两个JAVA REST Client版本：

　　1、java low level rest client:

　　低级别的rest客户端，通过http与集群交互，用户需自己编组请求JSON串，及解析响应JSON串。兼容所有Elasticsearch版本。

　　特点：maven引入

　　使用介绍: https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-low.html

　　2、java high rest client:

　　高级别的REST客户端，基于低级别的REST客户端，增加了编组请求JSON串、解析响应JSON串等相关API，使用的版本需要保存和ES服务一致的版本，否则会有版本问题。

　　从6.0.0开始加入的，目的是以java面向对象的方式进行请求、响应处理。

　　每个API支持同步、异步两种方式，同步方法之间返回一个结果对象。异步的方法以async为后缀，通过listener参数来通知结果。高级java resy客户端依赖Elasticsearch core pproject

　　兼容性说明：

　　依赖jdk1.8和Elasticsearch core project

二、Java Low Level Rest Client的使用

1、JAVA High Level Rest Client maven集成

<dependency>

    <groupId>org.elasticsearch.client</groupId>

    <artifactId>elasticsearch-rest-high-level-client</artifactId>

    <version>6.3.1</version>

</dependency>

版本：

Elasticsearch 6.3.1

pom文件：

<dependencies>

        <dependency>

            <groupId>org.elasticsearch.client</groupId>

            <artifactId>elasticsearch-rest-high-level-client</artifactId>

            <version>6.3.1</version>

        </dependency>

        <dependency>

            <groupId>org.apache.logging.log4j</groupId>

            <artifactId>log4j-api</artifactId>

            <version>2.7</version>

        </dependency>

        <dependency>

            <groupId>org.apache.logging.log4j</groupId>

            <artifactId>log4j-core</artifactId>

            <version>2.7</version>

        </dependency>

        <dependency>

            <groupId>net.sf.json-lib</groupId>

            <artifactId>json-lib</artifactId>

            <version>0.9</version>

        </dependency>

    </dependencies>

给定集群的多个节点地址，将客户端负载均衡地向这个节点地址集发请求：

import org.apache.http.HttpHost;

import org.elasticsearch.client.RestClient;

import org.elasticsearch.client.RestHighLevelClient;

/**

 * @Author: xiaolaotou

 * @Date: 2019/4/28

 */

public class ClientUtil {

    public static RestHighLevelClient getClient(){

        RestHighLevelClient client = new RestHighLevelClient(

                RestClient.builder(

                        new HttpHost("192.168.200.100",9200,"http"),

                        new HttpHost("192.168.200.101",9200,"http"),

                        new HttpHost("192.168.200.102",9200,"http"))

        );

        return client;

    }

}

2、创建索引

  /**

     * 创建索引

     * @throws Exception

     */

    public static void createindex()throws Exception{

        RestHighLevelClient client = ClientUtil.getClient();

        //1、创建索引，设置索引名

        CreateIndexRequest request = new CreateIndexRequest("mess");

        //2、设置索引的settings

        request.settings(Settings.builder()

                .put("index.number_of_shards",3)//分片数

                .put("index.number_of_replicas",1)//副本数

                .put("analysis.analyzer.default.tokenizer","ik_smart"))//默认分词器

        ;

        //3、设置索引的mappings

        request.mapping("_doc",

                "  {\n" +

                        "    \"_doc\": {\n" +

                        "      \"properties\": {\n" +

                        "        \"message\": {\n" +

                        "          \"type\": \"text\"\n" +

                        "        }\n" +

                        "      }\n" +

                        "    }\n" +

                        "  }",

                XContentType.JSON);

        //4、设置索引的别名

        request.alias(new Alias("mmm"));

        //5、发送方式

//        //5、1采用同步方式发送请求

        CreateIndexResponse response = client.indices().create(request);

//        处理响应

        boolean acknowledged = response.isAcknowledged();

        boolean shardsAcknowledged = response.isShardsAcknowledged();

        System.out.println("acknowledged = " + acknowledged);

        System.out.println("shardsAcknowledged = " + shardsAcknowledged);

        client.close();

        //5、2采用异步方法发送请求

//        ActionListener<CreateIndexResponse> listener = new ActionListener<CreateIndexResponse>() {

//            @Override

//            public void onResponse(CreateIndexResponse createIndexResponse) {

//                //处理响应

//                boolean acknowledged = createIndexResponse.isAcknowledged();

//                boolean shardsAcknowledged = createIndexResponse.isShardsAcknowledged();

//                System.out.println("shardsAcknowledged = " + shardsAcknowledged);

//                System.out.println("acknowledged = " + acknowledged);

//            }

//            @Override

//            public void onFailure(Exception e) {

//                System.out.println("创建索引异常 = " + e.getMessage());

//            }

//        };

//        client.indices().createAsync(request,listener);

//        client.close();

    }