Java操作Elasticsearch6.x简单示例

环境准备

因为还要使用idea编写Java，性能不够的机器不建议再开集群了，创建单节点的就行。

1. docker pull elasticsearch:6.5.4
2. docker run -d --name es -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" elasticsearch:6.5.4

Java操作

Maven

<dependencies>
    <!-- elasticsearch依赖2.x的log4j -->
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-api</artifactId>
        <version>2.8.2</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-core</artifactId>
        <version>2.8.2</version>
    </dependency>
    <!-- elasticsearch的客户端 -->
    <dependency>
        <groupId>org.elasticsearch.client</groupId>
        <artifactId>elasticsearch-rest-high-level-client</artifactId>
        <version>6.5.4</version>
    </dependency>
    <dependency>
        <groupId>org.elasticsearch</groupId>
        <artifactId>elasticsearch</artifactId>
        <version>6.5.4</version>
    </dependency>
    <!-- junit单元测试 -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
    <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-mapper-asl</artifactId>
        <version>1.9.13</version>
    </dependency>
</dependencies>

连接

package org.examples;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestHighLevelClient;

// 先创建连接，工具类
public class ESClient {

    public static RestHighLevelClient getClient(){
//        创建HttpHost对象
        HttpHost httpHost = new HttpHost("127.0.0.1",9200);
//      创建RestClientBuilder
        RestClientBuilder builder = RestClient.builder(httpHost);
        //      创建RestHighLevelClien对象
        RestHighLevelClient client = new RestHighLevelClient(builder);
        return client;
    }

}

示例

package org.examples;
import org.elasticsearch.action.admin.indices.get.GetIndexRequest;

import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.action.admin.indices.create.CreateIndexRequest;
import org.elasticsearch.action.admin.indices.create.CreateIndexResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.json.JsonXContent;
import org.codehaus.jackson.map.ObjectMapper;
import org.junit.Test;

import java.io.IOException;
import java.util.Date;

public class ESDemo {
    String index = "person";
    String type = "man";
    @Test
    public void createIndex() throws IOException {
     //1、 准备关于索引的settings
        Settings.Builder settings = Settings.builder()
                .put("number_of_shards", 3)
                .put("number_of_replicas", 1);


        //2、 准备关于索引的结构mappings
        XContentBuilder mappings = JsonXContent.contentBuilder()
                .startObject()
                    .startObject("properties")
                        .startObject("name")
                            .field("type","text")
                        .endObject()
                        .startObject("age")
                            .field("type","integer")
                        .endObject()
                        .startObject("birthday")
                             .field("type","date")
                             .field("format","yyyy-MM-dd")
                        .endObject()
                    .endObject()
                .endObject();

        //2 将settings 和 mappings封装成一个request对象
        CreateIndexRequest request = new CreateIndexRequest(index)
                .settings(settings)
                .mapping(type,mappings);
        //3   通过client对象去链接es并执行创建索引
        RestHighLevelClient client = ESClient.getClient();
        CreateIndexResponse response = client.indices().create(request, RequestOptions.DEFAULT);

        //测试
        System.out.println("response"+response.toString());
    }

    //检查索引是否存在
    @Test
    public void exists() throws IOException {
        //1 准备request对象
        GetIndexRequest request = new GetIndexRequest();
        request.indices(index);
        // 2 通过client去检查
        RestHighLevelClient client = ESClient.getClient();
        boolean exists = client.indices().exists(request, RequestOptions.DEFAULT);
        System.out.println(exists);
    }
}