SpringBoot整合ElasticSearch

SpringBoot整合ElasticSearch

1、选型

Java操作ElasticSearch有两种方式，一个是通过ES的9300端口使用TCP的方式操作，另一种是通过ES的9200端口使用HTTP的方式

1）9300 TCP

spring-data-elasticsearch:transport-api.jar

• springboot 版本不同， transport-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

2）9200 HTTP

• JestClient：非官方，更新慢

• RestTemplate：模拟发 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

综上所述，选择Elasticsearch-Rest-Client（elasticsearch-rest-high-level-client）是最优的选择，下面记录如何整合

Elasticsearch-Rest-Client 官方文档
https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high.html

2、SpringBoot整合

1）引入依赖

<properties>
    <java.version>1.8</java.version>
    //注意es版本
    <elasticsearch.version>7.4.2</elasticsearch.version> 
</properties>
    
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>7.4.2</version>
</dependency>

2）编写配置类

@Configuration
public class ElasticSearchConfig {

    public static final  RequestOptions COMMON_OPTIONS;

    static {
        // RequestOptions类保存了请求的部分，这些部分应该在同一个应用程序中的许多请求之间共享。
        // 创建一个singqleton实例，并在所有请求之间共享它。可以设置请求头之类的一些配置
        RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
        // builder.addHeader("Authorization", "Bearer " + TOKEN);
        // builder.setHttpAsyncResponseConsumerFactory(
        //         new HttpAsyncResponseConsumerFactory
        //                 .HeapBufferedResponseConsumerFactory(30 * 1024 * 1024 *1024));
        COMMON_OPTIONS = builder.build();
    }
	//创建ES实例
    @Bean
    public RestHighLevelClient restHighLevelClient(){
        return new RestHighLevelClient(RestClient.builder(new HttpHost(
                "192.168.XX.XXX",9200,"http"
        )));
    }

}

RequestOptions更多配置参考
https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-low-usage-requests.html#java-rest-low-usage-request-options
//创建ES实例参考
https://www.elastic.co/guide/en/elasticsearch/client/java-rest/master/java-rest-low-usage-initialization.html

3）测试检索

① 测试保存

@SpringBootTest
class SearchApplicationTests {

    @Autowired
    RestHighLevelClient restHighLevelClient;

    @Test
    void contextLoads() throws IOException {
    	//测试保存
        IndexRequest request = new IndexRequest("posts");
        request.id("1");
        String jsonString = "{" +
                "\"user\":\"kimchy\"," +
                "\"postDate\":\"2013-01-30\"," +
                "\"message\":\"trying out Elasticsearch\"" +
                "}";
        request.source(jsonString, XContentType.JSON);
        IndexResponse index=
        restHighLevelClient.index(request,ElasticSearchConfig.COMMON_OPTIONS);
        System.out.println("index-------------:"+ index);
    }
}

② 测试复杂检索

测试在Elastic进阶检索中使用kibana写的案例

参考ElasticSearchAPI

https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high-search.html

#搜索address中包含 mill的所有人的年龄分布以及平均年龄
 @Test
    void test() throws IOException {
        //搜索address中包含 mill的所有人的年龄分布以及平均年龄
        //  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();
        // 构建检索条件 address 包含 mill
        searchSourceBuilder.query(QueryBuilders.matchQuery("address","mill"));
        // 按照年龄值分布进行聚合
        TermsAggregationBuilder ageAgg  = AggregationBuilders.terms("ageAgg").field("age").size(10);
        searchSourceBuilder.aggregation(ageAgg);
        // 1.3 计算平均薪资
        AvgAggregationBuilder  balanceAvg = AggregationBuilders.avg("balanceAvg").field("balance");
        searchSourceBuilder.aggregation(balanceAvg);

        System.out.println("检索条件："+searchSourceBuilder.toString());
        searchRequest.source(searchSourceBuilder);

        //执行检索
        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, ElasticSearchConfig.COMMON_OPTIONS);

        //获取查询到的记录
        SearchHits hits = searchResponse.getHits();

        SearchHit[] searchHits = hits.getHits();

        //获取检索的分析信息
        Aggregations aggregations = searchResponse.getAggregations();
        // for (Aggregation aggregation : aggregations.asList()) {
        //     System.out.println("当前聚合名：" + aggregation.getName());
        // }
        Terms ageAgg1 = aggregations.get("ageAgg");
        for (Terms.Bucket bucket : ageAgg1.getBuckets()) {
            String keyAsString = bucket.getKeyAsString();
            System.out.println("年龄：" + keyAsString + " 岁的有 " + bucket.getDocCount() + " 人");
        }

        Avg balanceAvg1 = aggregations.get("balanceAvg");
        System.out.println("平均薪资: " + balanceAvg1.getValue());

  }