Java 从证书中获取公钥
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Obtaining public key from certificate
提问by javi
I'm trying to obtain the public key of a Certificate using the method:
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();
but I receive the following error:
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)
Does anyone know what this error is about?
有谁知道这个错误是关于什么的？
Thanks in advance
提前致谢
采纳答案by Dan
You have the wrong class imported for X509Certificate.
您为 导入了错误的类X509Certificate。
You are likely looking for java.security.cert.X509Certificatenot codec.x509.X509Certificate.
您可能正在寻找java.security.cert.X509Certificatenot codec.x509.X509Certificate。
回答by Sean
X509Certificate certificate = (X509Certificate)f.generateCertificate(fin);
PublicKey pk = certificate.getPublicKey();
since you are only pulling the public key, you can use the certificate class. The factory class will decide what type of a certificate to return.
由于您只是提取公钥，因此可以使用证书类。工厂类将决定返回什么类型的证书。
Certificate certificate = f.generateCertificate(fin);
PublicKey pk = certificate.getPublicKey();
If you need to cast this for antoher reason, check your imports and change it, X509Certificate should be coming from javax.security.cert
如果您出于其他原因需要强制转换，请检查您的导入并更改它，X509Certificate 应该来自 javax.security.cert
