ES之RestHighLevelClient 客户端连接基本配置

刚使用es的RestHighLevelClient连接了es集群，查了很多资料，请各位大佬指正。。。

maven的配置：

        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-client-sniffer</artifactId>
            <version>6.2.4</version>
        </dependency>

        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>6.2.4</version>
        </dependency>

        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>6.2.4</version>
        </dependency>

第一个是es的嗅探器，第二第三是es的版本以及es的RestHighLevelClient版本依赖。

首先初始化es的restClient，创建restClient的bulider类：

public class ClientBuilders {
	private static final String CLUSTER_HOSTNAME_PORT = "192.169.0.49:9200,192.169.0.50:9200";

	/**
	 * 初始化 clientBuilder的详细说明
	 * @return
	 */
	public static RestClientBuilder getClientBulider() {


		String [] hostNamesPort = CLUSTER_HOSTNAME_PORT.split(",");

		String host;
		int port;
		String[] temp;

		RestClientBuilder restClientBuilder = null;

		/*restClient 初始化*/
		if (0 != hostNamesPort.length) {
			for (String hostPort : hostNamesPort) {
				temp = hostPort.split(":");
				host = temp[0].trim();
				port = Integer.parseInt(temp[1].trim());
				restClientBuilder = RestClient.builder(new HttpHost(host, port, "http"));
			}
//这有问题，不应该用for的，写入多个httpHost可以在builder中用多个new HttpHost(host, port, "http")。
		}

		/*RestClientBuilder 在构建 RestClient 实例时可以设置以下的可选配置参数*/
		
		/*1.设置请求头，避免每个请求都必须指定*/
		Header[] defaultHeaders = new Header[]{
				new BasicHeader("header", "value")
		};
		restClientBuilder.setDefaultHeaders(defaultHeaders);

        /*2.设置在同一请求进行多次尝试时应该遵守的超时时间。默认值为30秒，与默认`socket`超时相同。
            如果自定义设置了`socket`超时，则应该相应地调整最大重试超时。*/

		restClientBuilder.setMaxRetryTimeoutMillis(10000);

		/*3.设置每次节点发生故障时收到通知的侦听器。内部嗅探到故障时被启用。*/
		restClientBuilder.setFailureListener(new RestClient.FailureListener() {
			@Override
			public void onFailure(HttpHost host) {
				// TODO 这里是当嗅探器测出某个节点有故障时，如何提醒用户，或有问题后做其他操
//作。
			}
		});

        /*4.设置修改默认请求配置的回调（例如：请求超时，认证，或者其他
         设置）。
         */
		restClientBuilder.setRequestConfigCallback(new RestClientBuilder.RequestConfigCallback() {

			@Override
			public RequestConfig.Builder customizeRequestConfig(RequestConfig.Builder requestConfigBuilder) {
				return requestConfigBuilder.setSocketTimeout(10000);
			}
		});

        /*5.//设置修改 http 客户端配置的回调（例如：ssl 加密通讯，线程IO的配置，或其他任何         设置）*/
		

// 简单的身份认证
		final CredentialsProvider credentialsProvider =
			    new BasicCredentialsProvider();
			credentialsProvider.setCredentials(AuthScope.ANY,
			    new UsernamePasswordCredentials("user", "password"));

		
		restClientBuilder.setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {

			@Override
			public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
				httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
	//线程设置	
		httpClientBuilder.setDefaultIOReactorConfig(IOReactorConfig.custom().setIoThreadCount(10).build());
				return httpClientBuilder;
			}
		});

		return restClientBuilder;
	}
}

之后，创建RestHighLevelClient 实例，调用clientBulider：

public class HighLevelClient {
	private static RestClientBuilder restClientBuilder = ClientBuilders.getClientBulider();

	// 实例化客户端
	private static RestHighLevelClient restHighLevelClient;
	// 嗅探器实例化
	private static Sniffer sniffer;
	
/**
 * 开启client，sniffer
 * @return
 */
	public RestHighLevelClient getClient() {
		restHighLevelClient = new RestHighLevelClient(restClientBuilder);
		//十秒刷新并更新一次节点
		sniffer = Sniffer.builder(restHighLevelClient.getLowLevelClient())
		        .setSniffAfterFailureDelayMillis(10000) 
		        .build();
		
		return restHighLevelClient;
	}

/**
 * 
 * @throws ESIoException
 * 关闭sniffer client
 */
	public void closeRestHighLevelClient() throws ESIoException {
		if (null != restHighLevelClient) {
			try {
				sniffer.close();
				restHighLevelClient.close();
			} catch (IOException e) {
				throw new ESIoException("RestHighLevelClient Client close exception", e);
			}
		}
	}
}

最后，创建创建函数类，创建main方法，调用client，就成功了：

public class EsOperate {
	public static void main(String[] args) throws IOException {
		HighLevelClient highLevelClient = new HighLevelClient();
		RestHighLevelClient client = highLevelClient.getClient();
		SearchRequest searchRequest = new SearchRequest("lib2");
		SearchResponse searchResponse = client.search(searchRequest);
		
		SearchHits hits = searchResponse.getHits(); 
		long totalHits = hits.getTotalHits();
		for (SearchHit hit : hits) {
		    String index = hit.getIndex(); //获取文档的index
		    String type = hit.getType(); //获取文档的type
		    String id = hit.getId(); //获取文档的id
		    Map<String, Object> sourceMap = hit.getSourceAsMap(); 
		    String sourceString = hit.getSourceAsString(); //获取文档内容，转换为json字符串。
		    
		    System.out.println(id+"$$$$$$$$$$"+index+"$$$$$$$$$$$$$$$$$"+type+"&&&&&&&&&&&&&&&&"+sourceString);
		}
		
		highLevelClient.closeRestHighLevelClient();
		
	}
}

es的集群安装以及Kibana的安装有时间再写。

 

参考文档：

https://segmentfault.com/a/1190000017119757

https://blog.youkuaiyun.com/HuoqilinHeiqiji/article/details/87972878

https://www.elastic.co/guide/en/elasticsearch/client/java-rest/6.7/java-rest-low-usage-initialization.html

https://github.com/codersfarm/elasticsearch/tree/master/elasticsearch6.x/src/main/java/com/elastic