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
1 package com.dajiangtai.djt_spider.elasticsearch;
2
3 import java.net.InetAddress;
4 import java.net.UnknownHostException;
5 import java.util.List;
6
7 import org.elasticsearch.client.transport.TransportClient;
8 import org.elasticsearch.cluster.node.DiscoveryNode;
9 import org.elasticsearch.common.settings.Settings;
10 import org.elasticsearch.common.transport.InetSocketTransportAddress;
11 import org.junit.Before;
12 import org.junit.Test;
13 /**
14 * 获取TransportClient
15 * @author 大讲台
16 *
17 */
18 public class ESTestClient {
19
20 /**
21 * 测试使用Java API 连接ElasticSearch 集群
22 *
23 * @throws UnknownHostException
24 */
25 @Test
26 public void test1() throws UnknownHostException {
27 // on startup
28 // 获取TransportClient
29 TransportClient client = TransportClient
30 .builder()
31 .build()
32 .addTransportAddress(
33 new InetSocketTransportAddress(InetAddress
34 .getByName("master"), 9300));
35
36 List<DiscoveryNode> connectedNodes = client.connectedNodes();
37 for (DiscoveryNode discoveryNode : connectedNodes) {
38 System.out.println("集群节点："+discoveryNode.getHostName());
39 }
40 // on shutdown
41 client.close();
42 }
43
44 /**
45 * 生成环境下，ElasticSearch集群名称非默认需要显示设置
46 *
47 * @throws UnknownHostException
48 */
49 @Test
50 public void test2() throws UnknownHostException {
51 Settings settings = Settings.settingsBuilder()
52 .put("cluster.name", "escluster").build();
53 // on startup
54 // 获取TransportClient
55 TransportClient client = TransportClient
56 .builder()
57 .settings(settings)
58 .build()
59 .addTransportAddress(
60 new InetSocketTransportAddress(InetAddress
61 .getByName("master"), 9300));
62
63 List<DiscoveryNode> connectedNodes = client.connectedNodes();
64 for (DiscoveryNode discoveryNode : connectedNodes) {
65 System.out.println("集群节点："+discoveryNode.getHostName());
66 }
67
68 // on shutdown
69 client.close();
70 }
71
72 /**
73 * 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
74 * 2、master节点挂机同时应用程序重启，则无法连接ElasticSearch集群
75 *
76 * @throws UnknownHostException
77 */
78 @Test
79 public void test3() throws UnknownHostException {
80
81 // 开启client.transport.sniff功能，探测集群所有节点
82 Settings settings = Settings.settingsBuilder()
83 .put("cluster.name", "escluster")
84 .put("client.transport.sniff", true).build();
85 // on startup
86 // 获取TransportClient
87 TransportClient client = TransportClient
88 .builder()
89 .settings(settings)
90 .build()
91 .addTransportAddress(
92 new InetSocketTransportAddress(InetAddress
93 .getByName("master"), 9300));
94
95 List<DiscoveryNode> connectedNodes = client.connectedNodes();
96 for (DiscoveryNode discoveryNode : connectedNodes) {
97 System.out.println("集群节点："+discoveryNode.getHostName());
98 }
99
100 // on shutdown
101 client.close();
102 }
103
104 /**
105 * 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
106 * 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
107 *
108 * @throws UnknownHostException
109 */
110 @Test
111 public void test4() throws UnknownHostException {
112
113 // 开启client.transport.sniff功能，探测集群所有节点
114 Settings settings = Settings.settingsBuilder()
115 .put("cluster.name", "escluster")
116 .put("client.transport.sniff", true).build();
117 // on startup
118 // 获取TransportClient
119 TransportClient client = TransportClient
120 .builder()
121 .settings(settings)
122 .build()
123 .addTransportAddress(
124 new InetSocketTransportAddress(InetAddress
125 .getByName("master"), 9300))
126 .addTransportAddress(
127 new InetSocketTransportAddress(InetAddress
128 .getByName("slave1"), 9300))
129 .addTransportAddress(
130 new InetSocketTransportAddress(InetAddress
131 .getByName("slave2"), 9300));
132
133 List<DiscoveryNode> connectedNodes = client.connectedNodes();
134 for (DiscoveryNode discoveryNode : connectedNodes) {
135 System.out.println("集群节点："+discoveryNode.getHostName());
136 }
137
138 // on shutdown
139 client.close();
140 }
141 }
