Elasticsearch-Rest-Client

通过 9300: TCP

• spring-data-elasticsearch:transport-api.jar;

  • springboot版本不同，ransport-api.jar不同，不能适配es版本
  • 7.x已经不建议使用，8以后就要废弃

    通过 9200: HTTP

• jestClient: 非官方，更新慢；

• RestTemplate：模拟HTTP请求，ES很多操作需要自己封装，麻烦；
• HttpClient：同上；
• Elasticsearch-Rest-Client：官方RestClient，封装了ES操作，API层次分明，上手简单；

最终选择 Elasticsearch-Rest-Client（elasticsearch-rest-high-level-client）； https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high.html

创建 Elasticsearch 检索服务模块

新建模块

pom.xml

<properties>
  <java.version>1.8</java.version>
  <!-- SpringBoot管理了elasticsearch的版本, 所有我们需要重写这个版本 -->
  <elasticsearch.version>7.4.2</elasticsearch.version>
</properties>
<dependencies>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
  </dependency>
  <dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
  </dependency>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
  </dependency>
  <!-- 用来转换JSON数据 -->
  <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.76</version>
  </dependency>
</dependencies>

编码测试

具体操作参考：es 操作API

编写配置类

配置客户端Bean 配置请求选项

package org.hong.gulimall.search.config;
import org.apache.http.HttpHost;
import org.elasticsearch.client.RequestOptions;
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 {
    /**
     * 配置请求选项
     * 参考：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-low-usage-requests.html#java-rest-low-usage-request-options
     */
    public static final RequestOptions COMMON_OPTIONS;
    static {
        RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
        // builder.addHeader("Authorization", "Bearer " + TOKEN);
        // builder.setHttpAsyncResponseConsumerFactory(
        //         new HttpAsyncResponseConsumerFactory
        //                 .HeapBufferedResponseConsumerFactory(30 * 1024 * 1024 * 1024));
        COMMON_OPTIONS = builder.build();
    }
    @Bean
    public RestHighLevelClient esRestClient() {
        return new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("192.168.200.130", 9200, "http")));
    }
}

测试配置类依赖注入

package org.hong.gulimall.search;
import org.elasticsearch.client.RestHighLevelClient;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest
class GulimallSearchApplicationTests {
    @Autowired
    RestHighLevelClient client;
    @Test
    void contextLoads() {
        System.out.println(client);
    }
}

测试存储数据 ( 更新 )

参考：Index API

package org.hong.gulimall.search;
import com.alibaba.fastjson.JSON;
import lombok.Data;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import org.hong.gulimall.search.config.ElasticsearchConfig;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.io.IOException;
@SpringBootTest
class GulimallSearchApplicationTests {
    @Autowired
    RestHighLevelClient client;
    @Data
    class User{
        private String userName;
        private String gender;
        private Integer age;
    }
    @Test
    void indexData() throws IOException {
        // 创建IndexRequest对象
        IndexRequest indexRequest = new IndexRequest();
        // 设置index
        indexRequest.index("users");
        // 设置id
        indexRequest.id("1");
        // 准备需要保存的数据
        User user = new User();
        user.setUserName("hong");
        user.setAge(18);
        user.setGender("男");
        // 将对象转换成JSON格式的数据
        String jsonString = JSON.toJSONString(user);
        // 设置资源
        indexRequest.source(jsonString, XContentType.JSON);
        // 执行操作
        IndexResponse index = client.index(indexRequest, ElasticsearchConfig.COMMON_OPTIONS);
        // 提取有用的响应数据
        System.out.println(index);
    }
}

控制台打印

IndexResponse[index=users,type=_doc,id=1,version=1,result=created,seqNo=0,primaryTerm=1,shards={"total":2,"successful":1,"failed":0}]

Kibana 检索查看

GET /users/_search

{
  "took" : 4,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "users",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "age" : 18,
          "gender" : "男",
          "userName" : "hong"
        }
      }
    ]
  }
}

测试复杂检索

参考： Search API

检索地址中带有 mill 的人员年龄分布和平均薪资

package org.hong.gulimall.search;
import com.alibaba.fastjson.JSON;
import lombok.Data;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.aggregations.Aggregations;
import org.elasticsearch.search.aggregations.bucket.terms.Terms;
import org.elasticsearch.search.aggregations.bucket.terms.TermsAggregationBuilder;
import org.elasticsearch.search.aggregations.metrics.Avg;
import org.elasticsearch.search.aggregations.metrics.AvgAggregationBuilder;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.hong.gulimall.search.config.ElasticsearchConfig;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.io.IOException;
@SpringBootTest
class GulimallSearchApplicationTests {
    @Autowired
    RestHighLevelClient client;
    @Data
    static class Account {
        private int account_number;
        private int balance;
        private String firstname;
        private String lastname;
        private int age;
        private String gender;
        private String address;
        private String employer;
        private String email;
        private String city;
        private String state;
    }
    @Test
    void searchData() throws IOException {
        // 1、创建检索请求
        SearchRequest searchRequest = new SearchRequest();
        // 指定索引
        searchRequest.indices("bank");
        // 指定DSL, 检索条件
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        // 1.1、构造检索条件 address 包含 mill
        searchSourceBuilder.query(QueryBuilders.matchQuery("address", "mill"));
        // 1.2 按照年龄值分布进行聚合
        TermsAggregationBuilder ageAgg = AggregationBuilders.terms("ageAgg").field("age").size(100);
        // 嵌套聚合subAggregation()方法
        //ageAgg.subAggregation(AggregationBuilders.avg("balanceAvg").field("balance"));
        searchSourceBuilder.aggregation(ageAgg);
        // 1.3 计算平均薪资
        AvgAggregationBuilder balanceAvg = AggregationBuilders.avg("balanceAvg").field("balance");
        searchSourceBuilder.aggregation(balanceAvg);
        searchRequest.source(searchSourceBuilder);
        System.out.println(searchSourceBuilder);
        // 2、执行检索
        SearchResponse searchResponse = client.search(searchRequest, ElasticsearchConfig.COMMON_OPTIONS);
        // 3、分析结果
        System.out.println(searchResponse);
        // 3.1、获取所有查询到的数据
        SearchHits hits = searchResponse.getHits();
        SearchHit[] searchHits = hits.getHits();
        for (SearchHit searchHit : searchHits) {
            // 获取JSON格式的数据
            String sourceAsString = searchHit.getSourceAsString();
            Account account = JSON.parseObject(sourceAsString, Account.class);
            System.out.println(account);
        }
        // 3.2、获取检索到的分析信息
        Aggregations aggregations = searchResponse.getAggregations();
        Terms ageAgg1 = aggregations.get("ageAgg");
        for (Terms.Bucket bucket : ageAgg1.getBuckets()) {
            System.out.println("年龄:" + bucket.getKey() + "\t" + "数量:" + bucket.getDocCount());
        }
        Avg avgBalance = aggregations.get("balanceAvg");
        System.out.println("平均薪资:" + avgBalance.getValue());
    }
}