从证书中获取公钥

Question

我正在尝试使用以下方法获取证书的公钥:

FileInputStream fin = new FileInputStream("PathToCertificate");
CertificateFactory f = CertificateFactory.getInstance("X.509");
X509Certificate certificate = (X509Certificate)f.generateCertificate(fin);
PublicKey pk = certificate.getPublicKey();

但是我收到以下错误:

Exception in thread "main" java.lang.ClassCastException: sun.security.x509.X509CertImpl cannot be cast to codec.x509.X509Certificate
        at sergas_testcertificates.Main.main(Main.java:54)

有谁知道这个错误是什么？

提前致谢

Answer 1

您导入了错误的类X509Certificate.

你很可能java.security.cert.X509Certificate不会codec.x509.X509Certificate.

Answer 2

X509Certificate certificate = (X509Certificate)f.generateCertificate(fin);
PublicKey pk = certificate.getPublicKey();

由于您只是拉公钥,因此可以使用证书类.工厂类将决定要返回的证书类型.

Certificate certificate = f.generateCertificate(fin);
PublicKey pk = certificate.getPublicKey();

如果您因为其他原因需要进行转换,请检查您的导入并进行更改,X509Certificate应该来自javax.security.cert