import android.security.keystore.KeyInfo; //导入依赖的package包/类
private String getPublicKey(String alias, AuthenticatorInfo authenticatorInfo) {
    try {
        KeyStore ks = KeyStore.getInstance("AndroidKeyStore");
        ks.load(null);
        KeyStore.Entry keyEntry = ks.getEntry(alias, null);
        if (keyEntry instanceof KeyStore.PrivateKeyEntry) {
            PrivateKey pk = ((KeyStore.PrivateKeyEntry) keyEntry).getPrivateKey();
            KeyFactory factory = KeyFactory.getInstance(pk.getAlgorithm(), "AndroidKeyStore");
            KeyInfo keyInfo = (KeyInfo) factory.getKeySpec(pk, KeyInfo.class);
            Certificate certificate = ks.getCertificate(alias);
            PublicKey publicKey = certificate.getPublicKey();
            String pkString = Base64.encodeToString(publicKey.getEncoded(), android.util.Base64.DEFAULT);
            if (authenticatorInfo != null) {
                authenticatorInfo.setPubKey(pkString);
                if (keyInfo.isInsideSecureHardware()) {
                    authenticatorInfo.setSecureHw(true);
                }
            }
            return pkString;
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return "";
}