1. 背景

1. 在做项目的过程，我们通常在本地开发时，需要连接单机的es进行测试，但是正式上线后，需要连接ES集群，并需要ssl认证，这种情况下，既要满足本地开发的需要，又要满足上线后集群的连接配置，故写下本文，用来记录
2. 我比较希望在SpringBoot启动的时候，就建立es连接，故使用了 @PostConstruct 注解，详见下文。

2. SpringBoot连接单机或集群ES

2.1 首先定义外部文件elasticsearch.properties

我将该文件存放在src/main/resources/config/elasticsearch.properties下【该文件当然也可以写在不同环境的yml文件中】

#ES配置文件
#是否是单机
elasticsearch.isSingleton=true
#ca位置
elasticsearch.capath=src/main/resources/ca/xxxx
#这个参数暂时保留
elasticsearch.keystorepass=
#账号密码
elasticsearch.username=username
elasticsearch.password=password
# 三个es节点信息
elasticsearch.node1Ip=11.14.11.72
elasticsearch.node1Port=9200
elasticsearch.node1Scheme=http
elasticsearch.node2Ip=22.94.239.72
elasticsearch.node2Port=9200
elasticsearch.node2Scheme=http
elasticsearch.node3Ip=33.94.239.72
elasticsearch.node3Port=9200
elasticsearch.node3Scheme=http

2.2 配置一个bean读取上述配置

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.PropertySource;
import org.springframework.stereotype.Component;


@Data
@Component
@ConfigurationProperties(prefix = "elasticsearch")
@PropertySource(value = {"classpath:config/elasticsearch.properties"}, encoding = "utf-8")
public class ESConfig {

    private Boolean isSingleton;

    private String capath;

    private String keystorepass;

    private String username;

    private String password;

    private String node1Ip;

    private Integer node1Port;

    private String node1Scheme;

    private String node2Ip;

    private Integer node2Port;

    private String node2Scheme;

    private String node3Ip;

    private Integer node3Port;

    private String node3Scheme;

}

2.3 ES连接配置类

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.impl.nio.client.HttpAsyncClientBuilder;
import org.apache.http.ssl.SSLContextBuilder;
import org.apache.http.ssl.SSLContexts;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.net.ssl.SSLContext;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.security.KeyStore;


@Slf4j
@Component
public class ESClient {

    public RestHighLevelClient restHighLevelClient;

    @Autowired
    private ESConfig esConfig;

    @PostConstruct
    private void init() {
        //初始化RestHighLevelClient
        this.initRestHighLevelClient();
    }

    private ESClient() {
    }

    private void initRestHighLevelClient() {
        try {
            if (restHighLevelClient == null) {
                if (!esConfig.getIsSingleton()) {
                    //正式环境 使用ssl认证 集群连接
                    log.info("******************ES集群连接开始****************");
                    restHighLevelClient = getClusterHighLevelClient();
                    log.info("******************ES集群连接成功****************");
                    return;
                }
                //单机连接
                log.info("******************单机ES连接开始****************");
                restHighLevelClient = getSingleHighLevelClient();
                log.info("******************单机ES连接成功****************");
            }
        } catch (Exception e) {
            log.error("es连接出现异常:{}", e.toString());
        }
    }

    /**
     * 集群连接
     *
     * @return
     * @throws Exception
     */
    private RestHighLevelClient getClusterHighLevelClient() throws Exception {
        Path trustStorePath = Paths.get(esConfig.getCapath());
        KeyStore truststore = KeyStore.getInstance("pkcs12");

        String keyStorePass = esConfig.getKeystorepass();
        InputStream is = Files.newInputStream(trustStorePath);
        truststore.load(is, keyStorePass.toCharArray());

        SSLContextBuilder sslBuilder = SSLContexts.custom().loadTrustMaterial(truststore, null);
        final SSLContext sslContext = sslBuilder.build();

        final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        credentialsProvider.setCredentials(AuthScope.ANY,
                new UsernamePasswordCredentials(esConfig.getUsername(), esConfig.getPassword()));
        log.info("连接ES集群: {}:{},{}:{},{}:{}", esConfig.getNode1Ip(), esConfig.getNode1Port(), esConfig.getNode2Ip(), esConfig.getNode2Port(), esConfig.getNode3Ip(), esConfig.getNode3Port());
        RestClientBuilder rclientBuilder = RestClient.builder(
                new HttpHost(esConfig.getNode1Ip(), esConfig.getNode1Port(), esConfig.getNode1Scheme()),
                new HttpHost(esConfig.getNode2Ip(), esConfig.getNode2Port(), esConfig.getNode2Scheme()),
                new HttpHost(esConfig.getNode3Ip(), esConfig.getNode3Port(), esConfig.getNode3Scheme()))
                .setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
                    @Override
                    public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
                        return httpClientBuilder.setSSLContext(sslContext)
                                .setSSLHostnameVerifier(new NoopHostnameVerifier())
                                .setDefaultCredentialsProvider(credentialsProvider);
                    }
                });
        restHighLevelClient = new RestHighLevelClient(rclientBuilder);
        return restHighLevelClient;
    }

    /**
     * 单机连接
     *
     * @return
     * @throws Exception
     */
    private RestHighLevelClient getSingleHighLevelClient() {
        final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials(esConfig.getUsername(), esConfig.getPassword()));
        log.info("连接单机ES: {}:{}", esConfig.getNode1Ip(), esConfig.getNode1Port());
        RestClientBuilder rclientBuilder = RestClient.builder(new HttpHost(esConfig.getNode1Ip(), esConfig.getNode1Port(), esConfig.getNode1Scheme()))
                .setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
                    @Override
                    public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
                        return httpClientBuilder.setSSLHostnameVerifier(new NoopHostnameVerifier())
                                .setDefaultCredentialsProvider(credentialsProvider);
                    }
                });
        restHighLevelClient = new RestHighLevelClient(rclientBuilder);
        return restHighLevelClient;
    }

}

3. 测试

import com.alibaba.fastjson.JSONObject;
import com.qs.myspringboottest.config.dbconnected.ESClient;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.io.IOException;


@RunWith(SpringRunner.class)
@SpringBootTest
public class ServiceTest1 {

    @Autowired
    private ESClient esClient;

    @Test
    public void myTest2() throws IOException {
       //获取esclient
        RestHighLevelClient restHighLevelClient = esClient.restHighLevelClient;
        SearchRequest searchRequest = new SearchRequest("indexTest");
        
        SearchSourceBuilder builder = new SearchSourceBuilder();
        builder.query(QueryBuilders.matchAllQuery());
        
        searchRequest.source(builder);

        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        System.out.println(JSONObject.toJSONString(searchResponse));
    }
}

然后在SpringBoot启动过程中就会建立ES连接

2021-06-08 14:37:05.496  INFO 22736 --- [           main] c.q.m.config.dbconnected.ESClient        : ******************单机ES连接开始****************
2021-06-08 14:37:05.499  INFO 22736 --- [           main] c.q.m.config.dbconnected.ESClient        : 连接单机ES: 11.14.11.72:9200
2021-06-08 14:37:08.312  INFO 22736 --- [           main] c.q.m.config.dbconnected.ESClient        : ******************单机ES连接结束****************