从证书中获取公钥

如何解决从证书中获取公钥

| 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关于什么的？ 提前致谢     

解决方法

        您为

X509Certificate

导入的类错误。 您可能会寻找

java.security.cert.X509Certificate

而不是

codec.x509.X509Certificate

。     ,        

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

由于您仅提取公共密钥，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();

如果出于其他原因需要强制转换，请检查导入并进行更改，X509Certificate应该来自javax.security.cert。