环境

服务器：centos6
elasticsearch：5+
java：1.8
工具：CRT

步骤

刚开始我是参照官网的来：

Transport Client

代码如下：

package elasticsearch.estutorial;//import 省略。。。public class EsUtils {public static TransportClient connectionEs(){//设置集群的名字Settings settings = Settings.builder().put("cluster.name", "yutao").put("client.transport.sniff", true).build();/*//忽视连接集群时名字验证builder.put("client.transport.ignore_cluster_name", true);//ping 一个节点时等待时间 默认5秒builder.put("client.transport.ping_timeout", "5s");//多久采样 ping / 节点列表和连接builder.put("client.transport.nodes_sampler_interval", "5s");*/try {//连接@SuppressWarnings("resource")TransportClient client = new PreBuiltTransportClient(settings).addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("192.168.116.131"), 9300));return client;} catch (UnknownHostException e) {e.printStackTrace();}return null;}public static void indexApi(){TransportClient client = connectionEs();String json = "{" +"\"user\":\"kimchy\"," +"\"postDate\":\"2013-01-30\"," +"\"message\":\"trying out Elasticsearch\"" +"}";List<DiscoveryNode> connectedNodes = client.connectedNodes();System.out.println(connectedNodes);IndexResponse response = client.prepareIndex("twitter", "tweet").setSource(json, XContentType.JSON).get();String index = response.getIndex();String type = response.getType();String id = response.getId();long version = response.getVersion();RestStatus status = response.status();System.out.println(index);System.out.println(type);System.out.println(id);System.out.println(version);System.out.println(status);}
}

main方法：

public static void main( String[] args ){EsUtils.indexApi();System.out.println( "Hello World!" );}

这个时候，它总是报，类似下面的错误：

Exception in thread "main" NoNodeAvailableException[None of the configured nodes are available: [{#transport#-1}{hbw6d5KVQ5KJZT2rK3Oz-A}{192.168.116.131}{192.168.116.131:9300}]]at org.elasticsearch.client.transport.TransportClientNodesService.ensureNodesAreAvailable(TransportClientNodesService.java:347)at org.elasticsearch.client.transport.TransportClientNodesService.execute(TransportClientNodesService.java:245)at org.elasticsearch.client.transport.TransportProxyClient.execute(TransportProxyClient.java:59)at org.elasticsearch.client.transport.TransportClient.doExecute(TransportClient.java:363)at org.elasticsearch.client.support.AbstractClient.execute(AbstractClient.java:408)at org.elasticsearch.action.ActionRequestBuilder.execute(ActionRequestBuilder.java:80)at org.elasticsearch.action.ActionRequestBuilder.execute(ActionRequestBuilder.java:54)at org.elasticsearch.action.ActionRequestBuilder.get(ActionRequestBuilder.java:62)at elasticsearch.estutorial.EsUtils.indexApi(EsUtils.java:63)at elasticsearch.estutorial.App.main(App.java:11)

网上的说法，就是：
①假设你改了集群的名字的话，代码里就要指定集群名称
②假设你指定了ip了，代码里同样也需要指定
③端口要使用9300

关键是上面三点我都做到了，可是还是不行。

后来猛然一想，9300的端口好像没有开放。

执行如下命令后，开放9300端口：

[yutao@localhost config]$ sudo firewall-cmd --permanent --add-port=9300/tcp
success
[yutao@localhost config]$ sudo firewall-cmd --reload
success
[yutao@localhost config]$ 
[yutao@localhost config]$ 
[yutao@localhost config]$ 
[yutao@localhost config]$ sudo firewall-cmd --list-all
public (active)target: defaulticmp-block-inversion: nointerfaces: ens33sources: services: dhcpv6-client http sshports: 7080/tcp 8080/tcp 9200/tcp 9300/tcp 9100/tcp 6379/tcp 5601/tcpprotocols: masquerade: noforward-ports: sourceports: icmp-blocks: rich rules: 

接着在执行代码，报错了，不过是另外一个错：

java missing authentication token for action [cluster:monitor/state]

这个错，错非常明显，因为我安装了x-pack，所以需要认证：

网上搜索了一番：

X-Pack for the Elastic Stack

installing_xpackclient

Java Client and Security

引入 xpackclient

<project ...><repositories><!-- add the elasticsearch repo --><repository><id>elasticsearch-releases</id><url>https://artifacts.elastic.co/maven</url><releases><enabled>true</enabled></releases><snapshots><enabled>false</enabled></snapshots></repository>...</repositories>...<dependencies><!-- add the x-pack jar as a dependency --><dependency><groupId>org.elasticsearch.client</groupId><artifactId>x-pack-transport</artifactId><version>5.6.4</version></dependency>...</dependencies>...</project>

使用类：PreBuiltXPackTransportClient

之后代码里使用PreBuiltXPackTransportClient，而不是PreBuiltTransportClient：

public static TransportClient connectionEs(){//设置集群的名字Settings settings = Settings.builder().put("cluster.name", "yutao").put("client.transport.sniff", true).put("xpack.security.transport.ssl.enabled", false).put("xpack.security.user", "elastic:changeme").build();/*//忽视连接集群时名字验证builder.put("client.transport.ignore_cluster_name", true);//ping 一个节点时等待时间 默认5秒builder.put("client.transport.ping_timeout", "5s");//多久采样 ping / 节点列表和连接builder.put("client.transport.nodes_sampler_interval", "5s");*/try {//连接@SuppressWarnings("resource")
//          TransportClient client = new PreBuiltTransportClient(settings)
//                                       .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("192.168.116.131"), 9300));TransportClient client = new PreBuiltXPackTransportClient(settings).addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("192.168.116.131"), 9300));return client;} catch (UnknownHostException e) {e.printStackTrace();}return null;}

这样就可以啦！

就我的测试项目而言，执行后的结果为：

no modules loaded
loaded plugin [org.elasticsearch.index.reindex.ReindexPlugin]
loaded plugin [org.elasticsearch.join.ParentJoinPlugin]
loaded plugin [org.elasticsearch.percolator.PercolatorPlugin]
loaded plugin [org.elasticsearch.script.mustache.MustachePlugin]
loaded plugin [org.elasticsearch.transport.Netty3Plugin]
loaded plugin [org.elasticsearch.transport.Netty4Plugin]
loaded plugin [org.elasticsearch.xpack.XPackPlugin]
[{ONRkJ5J}{ONRkJ5JxTH6Ic_E_sKhNAg}{4C0l5X7uQfShFJPj8pcXYQ}{192.168.116.131}{192.168.116.131:9300}{ml.max_open_jobs=10, ml.enabled=true}]
twitter
tweet
AWASSMU-4Wy1PJFus9gf
1
CREATED
Hello World!

好了，基础而已；

参考地址：

https://www.elastic.co/guide/en/x-pack/5.6/api-java.html#_installing_xpackclient

https://www.elastic.co/guide/en/x-pack/current/java-clients.html#java-clients

https://www.elastic.co/guide/en/x-pack/current/index.html