6.6.X版本的es配置了x-pack之后，如何在java中创建transportClient

大家好！
我现在用的6.6.2版本的elasticsearch，配置了xpack，并且设置了证书配置，配置项如下
xpack.security.enabled: true
xpack.security.transport.ssl.enabled: true

#enable PKI authentication
xpack.security.authc.realms.pki1.type: pki

#xpack.security.transport.ssl.key: certs/node-1/node-1.key
#xpack.security.transport.ssl.certificate: certs/node-1/node-1.crt
#xpack.security.transport.ssl.certificate_authorities: ["certs/ca/ca.crt"]

xpack.security.transport.ssl.verification_mode: certificate
xpack.security.transport.ssl.keystore.path: certs/elastic-certificates.p12
xpack.security.transport.ssl.truststore.path: certs/elastic-certificates.p12

#set to optional to allow unauthorized client authorize with other certificate
xpack.security.transport.ssl.client_authentication: optional
 
在java项目中创建TransportClient，配置项如下：
Settings settings = Settings.builder()
                        .put("cluster.name", clusterName)
                        .put("xpack.security.user", username+":"+password)
                        .put("xpack.security.enabled",true)
                        .put("xpack.security.transport.ssl.enabled", true)
//                        .put("client.transport.sniff", true)
启动java项目后，控制台报错：
PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
个人推测，这个应该是java里没有配置elasticsearch集群的证书，想请问一下，有没有大佬知道，要在java里面配置集群的哪个证书？我试了集群生成的elastic-certificates.p12，还有英文文档里的Creating a client certificate方法创建cer证书然后放到java的证书库里，都报错，
java报错信息为：
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:397) ~[na:1.8.0_191]
    at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:302) ~[na:1.8.0_191]
    at sun.security.validator.Validator.validate(Validator.java:262) ~[na:1.8.0_191]
    at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324) ~[na:1.8.0_191]
    at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:281) ~[na:1.8.0_191]
    at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:136) ~[na:1.8.0_191]
    at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1626) ~[na:1.8.0_191]
    ... 27 common frames omitted
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
es报错信息为：
Caused by: javax.net.ssl.SSLHandshakeException: no cipher suites in common
请问有没有大佬知道怎么解决？
拜谢~