# 1.4 程序连接ElasticSearch

# 1.4.1 SpringBoot集成ElasticSearch

SpringBoot是目前Java开发主流的开源框架，很多项目都是基于SpringBoot开发，在本书中，我们使用SpringBoot演示操作ES。

# 1. 创建项目

创建SpringBoot项目，导入Maven依赖导入es依赖需要的依赖、fastjson依赖，fastjson后续会用

<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>7.9.3</version>
</dependency>
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>7.9.3</version>
</dependency>
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.78</version>
</dependency>

# 2. 编写配置

新建配置类 ElasticSearchConfig 写入以下代码

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


@Configuration
public class ElasticSearchConfig {

    @Bean
    public RestHighLevelClient esRestClient(){
        // ES连接地址，集群写多个
        RestClientBuilder builder = RestClient.builder(
                new HttpHost("localhost", 9200, "http"));
        RestHighLevelClient client = new RestHighLevelClient(builder);
        return client;
    }
}

创建ES客户端对象 RestHighLevelClient 添加配置信息，注入到Spring容器中

新建控制层类 EsController 增加创建索引接口

package cn.chaosopen.es.controller;

import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.indices.CreateIndexRequest;
import org.elasticsearch.common.xcontent.XContentType;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.io.IOException;

@RestController
public class EsController {

    @Autowired
    private RestHighLevelClient client;

    @RequestMapping("/createIndex")
    public Boolean createIndex(String indexName) {
        CreateIndexRequest request = new CreateIndexRequest(indexName);
        request.mapping(
                "{\n" +
                        "  \"properties\": {\n" +
                        "    \"message\": {\n" +
                        "      \"type\": \"text\"\n" +
                        "    }\n" +
                        "  }\n" +
                        "}",
                XContentType.JSON);
        try {
            client.indices().create(request, RequestOptions.DEFAULT);
            return true;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return false;
    }
}