使用Spring Data Elasticsearch連接elasticsearch時，正常情況下只需要在application.properites文件中添加如下配置即可連接：
spring.data.elasticsearch.repositories.enabled = true spring.data.elasticsearch.cluster-name = es-cluster spring.data.elasticsearch.cluster-nodes = 127.0.0.1:9300 以看到Spring Data Elasticsearch連接elasticsearch很簡單。
上面說的是正常情況，但是有些情況下連接需要驗證。比如安裝x-pack（舊版本的Shield、Marvel等）之后，訪問elasticsearch就需要驗證（未開啟匿名訪問），默認用戶名/密碼是：elastic/changeme，參考官方文檔了解更多細節。
如果不做相應的修改就會報錯
org.elasticsearch.transport.RemoteTransportException: [i9Vl_pG][10.111.27.202:9300][cluster:monitor/nodes/liveness] Caused by: org.elasticsearch.ElasticsearchSecurityException: missing authentication token for action [cluster:monitor/nodes/liveness] at org.elasticsearch.xpack.security.support.Exceptions.authenticationError(Exceptions.java:36) ~[na:na] at org.elasticsearch.xpack.security.authc.DefaultAuthenticationFailureHandler.missingToken(DefaultAuthenticationFailureHandler.java:74) ~[na:na] at org.elasticsearch.xpack.security.authc.AuthenticationService$AuditableTransportRequest.anonymousAccessDenied(AuthenticationService.java:541) ~[na:na] at org.elasticsearch.xpack.security.authc.AuthenticationService$Authenticator.lambda$handleNullToken$17(AuthenticationService.java:357) ~[na:na] at org.elasticsearch.xpack.security.authc.AuthenticationService$Authenticator.handleNullToken(AuthenticationService.java:362) ~[na:na] at org.elasticsearch.xpack.security.authc.AuthenticationService$Authenticator.consumeToken(AuthenticationService.java:277) ~[na:na] at org.elasticsearch.xpack.security.authc.AuthenticationService$Authenticator.lambda$extractToken$7(AuthenticationService.java:249) ~[na:na] at org.elasticsearch.xpack.security.authc.AuthenticationService$Authenticator.extractToken(AuthenticationService.java:266) ~[na:na] at org.elasticsearch.xpack.security.authc.AuthenticationService$Authenticator.lambda$null$0(AuthenticationService.java:201) ~[na:na] at org.elasticsearch.action.ActionListener$1.onResponse(ActionListener.java:60) ~[elasticsearch-5.6.8.jar:5.6.8] at org.elasticsearch.xpack.security.authc.TokenService.getAndValidateToken(TokenService.java:239) ~[na:na] 在這樣的情況下，Spring Data Elasticsearch 該如何設置才能連接到 elasticsearch？目前最新版的 Spring Data Elasticsearch 2.1.6.Release 還不能通過配置的形式來完成。那要如何做，更換TransportClient即可！
修改依賴
<repository> <id>elasticsearch-releases</id> <url>https://artifacts.elastic.co/maven</url> <releases> <enabled>true</enabled> </releases> <snapshots> <enabled>false</enabled> </snapshots> </repository> ... <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-elasticsearch</artifactId> <exclusions> <exclusion> <groupId>org.elasticsearch.client</groupId> <artifactId>transport</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.elasticsearch.client</groupId> <artifactId>x-pack-transport</artifactId> <version>5.5.0</version> </dependency> x-pack-transport 的版本號保持與elasticsearch一致。
重新實例化 TransportClient
@Bean public TransportClient transportClient() throws UnknownHostException { TransportClient client = new PreBuiltXPackTransportClient(Settings.builder() .put("cluster.name", "es-cluster") .put("xpack.security.user", "elastic:changeme") .build()) .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300)); return client; } 就這么多，之前屬性文件中的配置可以刪除了，這樣就能保證連接驗證通過。