Springboot 整合Elasticsearch

1 java操作ES方式

1.1 操作ES 9300端口(TCP) 但开发中不在9300进行操作

ES集群节点通信使用的也是9300端口如果通过9300操作ES，需要与ES建立长连接  可通过引入spring-data-elasticsearch:transport-api.jar不在9300操作原因：1.springboot版本不同，transport-api.jar不同，不能适配ES版本2.官方在7.x版本已经不建议在9300操作ES，8以后会废弃ES通过9300操作的jar包

1.2 操作ES 9200端口(HTTP) 优选Elasticsearch-Rest-Client

通过9200对ES发送Http请求就可以了
1.使用第三方JestClient操作ES：更新慢
2.RestTemplate、HttpClient、OkHttp：发送HTTP请求，但如果操作ES一些DSL语句，需要自己封装，麻烦
3.Elasticsearch-Rest-Client（elasticsearch-rest-high-level-client）：官方RestClient，封装了ES操作，API层次分明，上手简单

2 整合

2.1引入elasticsearch-rest-high-level-client依赖

<!--elasticsearch-->
<dependency><groupId>org.elasticsearch.client</groupId><artifactId>elasticsearch-rest-high-level-client</artifactId><version>7.4.2</version>
</dependency>

刷新Maven 会发现elasticsearch和elasticsearch-rest-client版本是7.17.4，并不是7.4.2

原因是因为springboot对ES版本做了管理，当前springboot默认整合spring-data-elasticsearch操作ES

修改版本问题

如果使用Maven进行一个直接或间接继承spring-boot-dependencies（比如spring-boot-starter-parent）的构建，并想覆盖一个特定的
第三方依赖版本，可以添加<properties>标签，并重写第三方依赖版本

<properties><elasticsearch.version>7.4.2</elasticsearch.version>
</properties>

如果使用<scope>import</scope>，将spring-boot-dependencies添加到自己的dependencyManagement片段，
那么必须重新定义artifact而不是重写第三方依赖版本

<dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-dependencies</artifactId><version>2.7.3</version><type>pom</type><scope>import</scope></dependency><dependency><groupId>org.elasticsearch</groupId><artifactId>elasticsearch</artifactId><version>7.4.2</version></dependency><dependency><groupId>org.elasticsearch.client</groupId><artifactId>elasticsearch-rest-client</artifactId><version>7.4.2</version></dependency></dependencies>
</dependencyManagement>

2.2 添加ES配置

@Configuration
public class ElasticsearchConfig {/*** 配置请求选项* 参考：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.4/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();}@Beanpublic RestHighLevelClient esRestClient() {
//        RestHighLevelClient highLevelClient = new RestHighLevelClient(RestClient.builder(new HttpHost("192.168.179.101", 9200, "Http"),
//                new HttpHost("192.168.179.101", 9201, "Http")));RestHighLevelClient highLevelClient = new RestHighLevelClient(RestClient.builder(new HttpHost("192.168.179.101", 9200, "Http")));return highLevelClient;}}

2.3 测试及验证整合结果

@SpringBootTest
public class SearchApplicationTests {@Autowiredprivate RestHighLevelClient client;@Data@ToStringstatic 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;}/*** 在new_bank中搜索address中包含mill的所有人的年龄分布以及平均薪资*/@Testpublic void searchData() throws IOException {//1,创建检索请求SearchRequest searchRequest = new SearchRequest();//1.1,指定检索索引searchRequest.indices("new_bank");//1.2,构造检索条件SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();searchSourceBuilder.query(QueryBuilders.matchQuery("address", "Mill"));//1.2.1,按照年龄分布进行聚合TermsAggregationBuilder ageAgg = AggregationBuilders.terms("ageAgg").field("age").size(10);searchSourceBuilder.aggregation(ageAgg);//1.2.2,计算平均薪资AvgAggregationBuilder avgBalance = AggregationBuilders.avg("avgBalance").field("balance");searchSourceBuilder.aggregation(avgBalance);System.out.println("检索条件" + searchSourceBuilder);searchRequest.source(searchSourceBuilder);//2,执行同步检索SearchResponse searchResponse = client.search(searchRequest, ElasticsearchConfig.COMMON_OPTIONS);System.out.println("执行检索结果" + searchResponse);//3,提取命中结果hitsSearchHits hits = searchResponse.getHits();SearchHit[] hitsHits = hits.getHits();for (SearchHit hitsHit : hitsHits) {String sourceAsString = hitsHit.getSourceAsString();Account account = JSONObject.parseObject(sourceAsString, Account.class);System.out.println(account);}//4,提取聚合信息Aggregations aggregations = searchResponse.getAggregations();Terms ageAggRes = aggregations.get("ageAgg");List<? extends Terms.Bucket> aggResBuckets = ageAggRes.getBuckets();for (Terms.Bucket aggResBucket : aggResBuckets) {System.out.println("年龄：" + aggResBucket.getKeyAsString() + "总和：" + aggResBucket.getDocCount());}Avg balance = aggregations.get("avgBalance");System.out.println(balance.getValue());}/*** https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.4/java-rest-high-document-index.html*/@Testpublic void testEsAdd() throws IOException {//指定索引IndexRequest indexRequest = new IndexRequest("users");//指定idindexRequest.id("1");//封装数据User user = new User();user.setUserName("张三");user.setAge(27);user.setGender("M");String jsonString = JSONObject.toJSONString(user);//指定数据类型为JSONindexRequest.source(jsonString, XContentType.JSON);//执行同步操作IndexResponse index = client.index(indexRequest, ElasticsearchConfig.COMMON_OPTIONS);System.out.println(index);}@Dataclass User {private String userName;private String gender;private Integer age;}}

kibanaGET /users/_search
{"took" : 1,"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" : 27,"gender" : "M","userName" : "张三"}}]}
}