使用Bouncy-Castle库从证书读取SubjectAlternativeNames

import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.x509.extension.X509ExtensionUtil;

import java.io.FileInputStream;
import java.security.KeyStore;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import java.util.Collection;
import java.util.List;

public class CertificateReader {
    public static void main(String[] args) throws Exception {
        // 添加Bouncy-Castle提供者
        Security.addProvider(new BouncyCastleProvider());

        // 加载证书
        KeyStore keyStore = KeyStore.getInstance("JKS");
        FileInputStream fis = new FileInputStream("path/to/keystore.jks");
        keyStore.load(fis, "password".toCharArray());
        fis.close();

        // 获取证书
        Certificate certificate = keyStore.getCertificate("alias");

        // 转换为X509Certificate
        X509Certificate x509Certificate = (X509Certificate) certificate;

        // 获取SubjectAlternativeNames扩展字段
        Collection<List<?>> subjectAlternativeNames = x509Certificate.getSubjectAlternativeNames();

        // 解析SubjectAlternativeNames
        if (subjectAlternativeNames != null) {
            for (List<?> san : subjectAlternativeNames) {
                int type = (Integer) san.get(0);
                Object value = san.get(1);

                // 根据类型进行处理
                switch (type) {
                    case 0: // OtherName
                        // 处理OtherName类型
                        break;
                    case 1: // RFC822Name
                        // 处理RFC822Name类型
                        break;
                    case 2: // DNSName
                        // 处理DNSName类型
                        break;
                    case 3: // X400Address
                        // 处理X400Address类型
                        break;
                    case 4: // DirectoryName
                        // 处理DirectoryName类型
                        break;
                    case 5: // EDIPartyName
                        // 处理EDIPartyName类型
                        break;
                    case 6: // URI
                        // 处理URI类型
                        break;
                    case 7: // IPAddress
                        // 处理IPAddress类型
                        break;
                    case 8: // RegisteredID
                        // 处理RegisteredID类型
                        break;
                }
            }
        }
    }
}