给定一个公钥字符串，如何创建RSAPublicKey的实例

import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

public class RSAPublicKeyExample {
    public static void main(String[] args) throws Exception {
        String publicKeyString = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAn9z..."; // 公钥字符串
        byte[] publicKeyBytes = Base64.getDecoder().decode(publicKeyString); // 将公钥字符串解码为字节数组

        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKeyBytes); // 创建X509EncodedKeySpec对象
        KeyFactory keyFactory = KeyFactory.getInstance("RSA"); // 指定使用RSA加密算法
        PublicKey publicKey = keyFactory.generatePublic(keySpec); // 生成Key对象

        RSAPublicKey rsaPublicKey = (RSAPublicKey) publicKey; // 强制转换为RSAPublicKey类型

        // 打印生成的RSAPublicKey实例信息
        System.out.println("Algorithm: " + rsaPublicKey.getAlgorithm());
        System.out.println("Modulus: " + rsaPublicKey.getModulus());
        System.out.println("Public Exponent: " + rsaPublicKey.getPublicExponent());
    }
}