private String getCertCN ( X509Certificate x509 ) throws CertificateParsingException { X500Principal principal = x509 . getSubjectX500Principal ( ) ; String subjectName = principal . getName ( ) ; String [ ] fields = subjectName . split ( "," ) ; for ( String field : fields ) { if ( field . startsWith ( "CN=" ) ) { String serverName = field . substring ( 3 ) ; return serverName . toLowerCase ( ) ; } } throw new CertificateParsingException ( "Certificate CN not found" ) ; }
Read the CN out of the cert