1. 导入依赖

<dependency>
    <groupId>co.elastic.clients</groupId>
    <artifactId>elasticsearch-java</artifactId>
    <version>8.4.1</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.12.3</version>
</dependency>
<dependency>
    <groupId>jakarta.json</groupId>
    <artifactId>jakarta.json-api</artifactId>
    <version>2.0.1</version>
</dependency>

2. 配置文件

• 配置springboot的application.yml

spring:
  elasticsearch:
    rest:
      # 是否启用es
      enable: true
      uris: localhost:9200
      host: localhost
      port: 9200
      username: elastic
      password: 123456
      index: indexName
      crtName: http_ca.crt

• 配置es的自签证书

  • 执行如下命令将es容器中的crt文件复制到本地
    docker cp 容器名称:/usr/share/elasticsearch/config/certs/http_ca.crt .
  • 将crt文件放至springboot项目的resource路径下

3. 编写Java Client配置

package com.dp.search.config;

import co.elastic.clients.elasticsearch.ElasticsearchClient;
import co.elastic.clients.json.jackson.JacksonJsonpMapper;
import co.elastic.clients.transport.ElasticsearchTransport;
import co.elastic.clients.transport.rest_client.RestClientTransport;
import lombok.extern.slf4j.Slf4j;
import org.apache.http.HttpHost;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.conn.ssl.NoopHostnameVerifier;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.ssl.SSLContextBuilder;
import org.apache.http.ssl.SSLContexts;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;

import javax.annotation.PostConstruct;
import javax.net.ssl.SSLContext;
import java.io.IOException;
import java.io.InputStream;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;

/**
 * es8的Java客户端配置
 * author：Geng
 */
@Configuration
@Slf4j
public class ElasticSearchConfig {

    @Value("${spring.elasticsearch.rest.host}")
    private String host;
    @Value("${spring.elasticsearch.rest.enable}")
    private boolean enable;
    @Value("${spring.elasticsearch.rest.port}")
    private int port;
    @Value("${spring.elasticsearch.rest.username}")
    private String userName;
    @Value("${spring.elasticsearch.rest.password}")
    private String passWord;
    @Value("${spring.elasticsearch.rest.crtName}")
    private String tempCrtName;

    private static String crtName;

    @PostConstruct
    private void init() {
        crtName = tempCrtName;
    }

    /**
     * 解析配置的字符串，转为HttpHost对象数组
     *
     * @return
     */
    private HttpHost toHttpHost() {
        HttpHost httpHost = new HttpHost(host, port, "https");
        return httpHost;
    }

    @Bean
    public ElasticsearchClient clientByPasswd() throws Exception {
        ElasticsearchTransport transport = getElasticsearchTransport(userName, passWord, toHttpHost());
        return new ElasticsearchClient(transport);
    }

    private static SSLContext buildSSLContext() {
        ClassPathResource resource = new ClassPathResource(crtName);
        SSLContext sslContext = null;
        try {
            CertificateFactory factory = CertificateFactory.getInstance("X.509");
            Certificate trustedCa;
            try (InputStream is = resource.getInputStream()) {
                trustedCa = factory.generateCertificate(is);
            }
            KeyStore trustStore = KeyStore.getInstance("pkcs12");
            trustStore.load(null, null);
            trustStore.setCertificateEntry("ca", trustedCa);
            SSLContextBuilder sslContextBuilder = SSLContexts.custom()
                    .loadTrustMaterial(trustStore, null);
            sslContext = sslContextBuilder.build();
        } catch (CertificateException | IOException | KeyStoreException | NoSuchAlgorithmException |
                 KeyManagementException e) {
            log.error("ES连接认证失败", e);
        }

        return sslContext;
    }

    private static ElasticsearchTransport getElasticsearchTransport(String username, String passwd, HttpHost... hosts) {
        // 账号密码的配置
        final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials(username, passwd));

        // 自签证书的设置，并且还包含了账号密码
        RestClientBuilder.HttpClientConfigCallback callback = httpAsyncClientBuilder -> httpAsyncClientBuilder
                .setSSLContext(buildSSLContext())
                .setSSLHostnameVerifier(NoopHostnameVerifier.INSTANCE)
                .setDefaultCredentialsProvider(credentialsProvider);

        // 用builder创建RestClient对象
        RestClient client = RestClient
                .builder(hosts)
                .setHttpClientConfigCallback(callback)
                .build();
        return new RestClientTransport(client, new JacksonJsonpMapper());
    }

}

4. 测试连接

@SpringBootTest
public class GulimallSearchApplicationTests {

    @Autowired
    private ElasticsearchClient elasticsearchClient;

    @Test
    public void contextLoads() {
        SearchResponse<Object> search = null;
        try {
            search = elasticsearchClient.search(s -> s
                            .index("bank")
                            //查询name字段包含hello的document(不使用分词器精确查找)
                            .query(q -> q
                                    .match(t -> t
                                            .field("balance")
                                            .query(16418)
                                    )), Object.class
            );
        } catch (IOException e) {
            e.printStackTrace();
        }
        System.out.println(search);
    }

    @SneakyThrows
    @Test
    public void Search() {
        String searchText = "mill";

        Query query = MatchQuery.of(m -> m
                .field("address")
                .query(searchText))._toQuery();

        SearchResponse<userTest> search = elasticsearchClient.search(s -> s
                .index("bank")
                .query(query)
                .aggregations("ageAgg",a->a
                        .terms(t->t
                                .field("age")
                                .size(10))
                )
                .aggregations("ageAve",a->a
                        .avg(av->av
                                .field("age"))
                )
                .aggregations("balanceAvg",a->a
                        .avg(av->av
                                .field("balance"))
                ), userTest.class);

        System.out.println(search);

        AvgAggregate ageAve = search.aggregations().get("ageAve").avg();
        JSONObject parse = (JSONObject)JSON.parse(String.valueOf(ageAve));
        System.out.println("平均年龄："+parse.get("value"));

        AvgAggregate balanceAvg = search.aggregations().get("balanceAvg").avg();
        JSONObject parse1 =(JSONObject) JSON.parse(String.valueOf(balanceAvg));
        System.out.println("平均工资："+parse1.get("value"));

        List<LongTermsBucket> ageAgg = search.aggregations().get("ageAgg").lterms().buckets().array();
        for (LongTermsBucket longTermsBucket : ageAgg) {
            System.out.println("年龄："+longTermsBucket.key()+"数量："+longTermsBucket.docCount());
        }

        List<Hit<userTest>> hits = search.hits().hits();
        for (Hit<userTest> hit: hits) {
            userTest source = hit.source();
            System.out.println("内部数据：" + source + " 得分 " + hit.score());
            System.out.println(source.getEmail());

        }
    }
}