數字證書中讀取PublicKey

1. 讀取https簽發證書中的key

 1) 在下面的代碼中,是實現讀取證書字符串來讀取key的,CERTIFICATE 就是一個證書的字符串, 而方法cf.generateCertificate() 接受的是一個InputStream 流,當然這個地方也可以讀取一個文件 new FileInputSream("file path")即可!

public String getCertificateKey() {
        CertificateFactory cf = null;
        PublicKey publicKey = null;
        try {
            cf = CertificateFactory.getInstance("X.509");
            //DataInputStream  di = new DataInputStream("");
            X509Certificate cert = (X509Certificate)cf.generateCertificate(new ByteArrayInputStream(CERTIFICATE.getBytes()));
            publicKey = cert.getPublicKey();
        } catch (Exception e) {
            e.printStackTrace();
        }
        byte[] publicKeyString = Base64.encode(publicKey.getEncoded(), Base64.DEFAULT);
        String publickey = new String(publicKeyString);
        System.out.println("-----------------公鑰--------------------");
        System.out.println(publickey);
        System.out.println("-----------------公鑰--------------------");
        return publickey;
    }

　2) 這里的 X509Certificate 文件是 import java.security.cert.X509Certificate; 包路徑下的, 

 

 

 

public String getCertificateKey() {
    CertificateFactory cf = null;
PublicKey publicKey = null;
    try {
        cf = CertificateFactory.getInstance("X.509");
//DataInputStream  di = new DataInputStream("");
X509Certificate cert = (X509Certificate)cf.generateCertificate(new ByteArrayInputStream(CERTIFICATE.getBytes()));
publicKey = cert.getPublicKey();
} catch (Exception e) {
        e.printStackTrace();
}
    byte[] publicKeyString = Base64.encode(publicKey.getEncoded(), Base64.DEFAULT);
String publickey = new String(publicKeyString);
System.out.println("-----------------公鑰--------------------");
System.out.println(publickey);
System.out.println("-----------------公鑰--------------------");
    return publickey;
}