Key of string in Java RSA

I use RSA encryption in my application To store the generated public key, I convert it to a string and save it in the database

Key publicKey=null;
    Key privateKey=null;

    KeyPair keyPair=RsaCrypto.getKeyPairRSA(1024);
    publicKey=keyPair.getPublic();
    privateKey=keyPair.getPrivate();



    String publicK=Base64.encodeToString(publicKey.getEncoded(),Base64.DEFAULT);
    String privateK=Base64.encodeToString(privateKey.getEncoded(),Base64.DEFAULT);

I saved strings, publick and privatek My problem is that when I want to encrypt / decrypt text with RSA and use my saved key in string format, I don't know how to convert it to key

public static String encrypt(Key publicKey,String inputText){
    byte[]encodedBytes=null;
    String encryptedText="";
    try {
        Cipher cipher=Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE,publicKey);
        encodedBytes=cipher.doFinal(inputText.getBytes());
    } catch (Exception e) {Log.e("Error","RSA encryption error");  }

    encryptedText=Base64.encodeToString(encodedBytes,Base64.DEFAULT);
    return encryptedText;
}

Do you have any ideas? Thank you.

Solution

To convert public K (string) to public key:

byte[] keyBytes = Base64.decode(publicK.getBytes("utf-8"));
X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey key = keyFactory.generatePublic(spec);

To convert privatek (string) to a private key:

byte[] keyBytes = Base64.decode(privateK.getBytes("utf-8"));
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory fact = KeyFactory.getInstance("RSA");
PrivateKey priv = fact.generatePrivate(keySpec);