如何在Java中从X500Name中提取C，ST，L，O，OU，CN，E？

import org.bouncycastle.asn1.x500.X500Name;
import org.bouncycastle.asn1.x500.RDN;
import org.bouncycastle.asn1.x500.style.BCStyle;

public class X500NameExtractor {
    public static void main(String[] args) {
        X500Name x500Name = new X500Name("C=US, ST=California, L=San Francisco, O=Example Company, OU=IT Department, CN=John Doe, E=johndoe@example.com");

        RDN[] rdns = x500Name.getRDNs();

        for (RDN rdn : rdns) {
            String rdnType = rdn.getFirst().getType().getId();
            String rdnValue = rdn.getFirst().getValue().toString();

            switch (rdnType) {
                case BCStyle.C:
                    System.out.println("C (Country): " + rdnValue);
                    break;
                case BCStyle.ST:
                    System.out.println("ST (State/Province): " + rdnValue);
                    break;
                case BCStyle.L:
                    System.out.println("L (Locality/City): " + rdnValue);
                    break;
                case BCStyle.O:
                    System.out.println("O (Organization): " + rdnValue);
                    break;
                case BCStyle.OU:
                    System.out.println("OU (Organizational Unit): " + rdnValue);
                    break;
                case BCStyle.CN:
                    System.out.println("CN (Common Name): " + rdnValue);
                    break;
                case BCStyle.E:
                    System.out.println("E (Email Address): " + rdnValue);
                    break;
                default:
                    System.out.println("Unknown RDN type: " + rdnType);
                    break;
            }
        }
    }
}