ElasticSearch8之后的版本默认是通过https访问的

通过https访问

import co.elastic.clients.elasticsearch.ElasticsearchClient;
import co.elastic.clients.json.jackson.JacksonJsonpMapper;
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.impl.client.BasicCredentialsProvider;
import org.elasticsearch.client.RestClient;
import co.elastic.clients.transport.ElasticsearchTransport;
import co.elastic.clients.transport.rest_client.RestClientTransport;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.net.ssl.*;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;

@Configuration
public class ElasticsearchConfig {

    @Bean
    public ElasticsearchClient client() throws Exception {

        final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        //设置账号密码
        credentialsProvider.setCredentials(
                AuthScope.ANY, new UsernamePasswordCredentials("elastic", "elastic"));

        final SSLContext sslContext = SSLContext.getInstance("TLS");
        sslContext.init(null, new TrustManager[]{new MyTrustManager()}, new SecureRandom());
        final MyHostnameVerifier hostnameVerifier = new MyHostnameVerifier();
        RestClient restClient = RestClient.builder(new HttpHost("127.0.0.1", 9200, "https"))
                .setHttpClientConfigCallback(httpClientBuilder->httpClientBuilder
                        .setDefaultCredentialsProvider(credentialsProvider)
                        .setSSLContext(sslContext)
                        .setSSLHostnameVerifier(hostnameVerifier)
                ).build();
        ElasticsearchTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        ElasticsearchClient client = new ElasticsearchClient(transport);
        return client;
    }


    /**
     * 重写HostnameVerifier接口
     */
    private static class MyHostnameVerifier implements HostnameVerifier {
        @Override
        public boolean verify(String hostname, SSLSession session) {
            return true;
        }
    }

    private static class MyTrustManager implements X509TrustManager {
        @Override
        public void checkClientTrusted(X509Certificate[] chain, String authType) {
        }
        @Override
        public void checkServerTrusted(X509Certificate[] chain, String authType) {
        }
        @Override
        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }
    }
}

https改为http

也可以改为http访问，修改配置文件elasticsearch.yml 把下面配置改为false 重启就好了。

xpack.security.http.ssl:
  enabled: false