ElasticSearch client API

 

从运行结果看并没有打印节点信息出来

 

从结果看出来，集群节点信道打印出来了，不过这种方法有个问题，就是当我们连接的节点挂掉了，就没法连接整个集群了，这个时候我们就利用他的一个嗅探的功能。

从这里我们可以看到，通过嗅探功能把集群的三个节点都打印出来了

实际上我们只传入master节点，但是同过master节点探测到其他两个节点信息

但是但应用重启之后master节点挂掉了就不能连接集群了，为了防止容错性，我们就多设置几个节点

参考代码ESTestClient.java

package com.dajiangtai.djt_spider.elasticsearch;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.List;

import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.InetSocketTransportAddress;
import org.junit.Before;
import org.junit.Test;
/**
 * 获取TransportClient
 * @author 大讲台
 *
 */
public class ESTestClient {

    /**
     * 测试使用Java API 连接ElasticSearch 集群
     * 
     * @throws UnknownHostException
     */
    @Test
    public void test1() throws UnknownHostException {
        // on startup
        // 获取TransportClient
        TransportClient client = TransportClient
                .builder()
                .build()
                .addTransportAddress(
                        new InetSocketTransportAddress(InetAddress
                                .getByName("master"), 9300));
        
        List<DiscoveryNode> connectedNodes = client.connectedNodes();
        for (DiscoveryNode discoveryNode : connectedNodes) {
            System.out.println("集群节点："+discoveryNode.getHostName());
        }
        // on shutdown
        client.close();
    }

    /**
     * 生成环境下，ElasticSearch集群名称非默认需要显示设置
     * 
     * @throws UnknownHostException
     */
    @Test
    public void test2() throws UnknownHostException {
        Settings settings = Settings.settingsBuilder()
                .put("cluster.name", "escluster").build();
        // on startup
        // 获取TransportClient
        TransportClient client = TransportClient
                .builder()
                .settings(settings)
                .build()
                .addTransportAddress(
                        new InetSocketTransportAddress(InetAddress
                                .getByName("master"), 9300));
        
        List<DiscoveryNode> connectedNodes = client.connectedNodes();
        for (DiscoveryNode discoveryNode : connectedNodes) {
            System.out.println("集群节点："+discoveryNode.getHostName());
        }

        // on shutdown
        client.close();
    }

    /**
     * 1、启动应用程序之后，client.transport.sniff能保证即使master挂掉也能连接上集群
     * 2、master节点挂机同时应用程序重启，则无法连接ElasticSearch集群
     * 
     * @throws UnknownHostException
     */
    @Test
    public void test3() throws UnknownHostException {

        // 开启client.transport.sniff功能，探测集群所有节点
        Settings settings = Settings.settingsBuilder()
                .put("cluster.name", "escluster")
                .put("client.transport.sniff", true).build();
        // on startup
        // 获取TransportClient
        TransportClient client = TransportClient
                .builder()
                .settings(settings)
                .build()
                .addTransportAddress(
                        new InetSocketTransportAddress(InetAddress
                                .getByName("master"), 9300));

        List<DiscoveryNode> connectedNodes = client.connectedNodes();
        for (DiscoveryNode discoveryNode : connectedNodes) {
            System.out.println("集群节点："+discoveryNode.getHostName());
        }

        // on shutdown
        client.close();
    }

    /**
     * 1、启动应用程序之后，client.transport.sniff能保证即使master挂掉也能连接上集群
     * 2、设置多节点，防止其中一个节点挂机同时应用程序重启，无法连接ElasticSearch集群问题
     * 
     * @throws UnknownHostException
     */
    @Test
    public void test4() throws UnknownHostException {

        // 开启client.transport.sniff功能，探测集群所有节点
        Settings settings = Settings.settingsBuilder()
                .put("cluster.name", "escluster")
                .put("client.transport.sniff", true).build();
        // on startup
        // 获取TransportClient
        TransportClient client = TransportClient
                .builder()
                .settings(settings)
                .build()
                .addTransportAddress(
                        new InetSocketTransportAddress(InetAddress
                                .getByName("master"), 9300))
                .addTransportAddress(
                        new InetSocketTransportAddress(InetAddress
                                .getByName("slave1"), 9300))
                .addTransportAddress(
                        new InetSocketTransportAddress(InetAddress
                                .getByName("slave2"), 9300));
        
        List<DiscoveryNode> connectedNodes = client.connectedNodes();
        for (DiscoveryNode discoveryNode : connectedNodes) {
            System.out.println("集群节点："+discoveryNode.getHostName());
        }

        // on shutdown
        client.close();
    }
}