How to create a wallet file for existing account&

Question

I found this way of creating a new ethereum account with web3j. But what if I want to create a wallet file for an already registered account? I need this because most of the web3j functions require a wallet file.

1. Generate a key-pair Keys.createEcKeyPair()
2. Create the wallet Wallet.createStandard(seed, keyPair)

Answer 1

you don't need always a wallet file, you can do something like this

/**
 * system wallet.
 */
private Credentials credentials;

/**
 * Get wallet from PrivateKey.
 * @param privateKeyInHex the private key
 */
private Credentials getCredentailFromPrivteKey(String privateKeyInHex) {
    BigInteger privateKeyInBT = new BigInteger(privateKeyInHex, 16);
    ECKeyPair aPair = ECKeyPair.create(privateKeyInBT);
    Credentials aCredential = Credentials.create(aPair);
    credentials = aCredential;
}