Check Bitcoin address balance from blockchain

Question

I am a merchant that accepts bitcoins, and I'm building my own desktop client for receiving them in Java.

When I receive a transaction, I would like to be able to see in my client how much bitcoin is stored in the address that I am receiving from.

I have the full blockchain downloaded on my computer.

How can I access the balance of an address from the blockchain? I would like to be able to do this offline by accessing the blockchain stored on my hard drive.

Thanks in advance

Answer 1

Perhaps you can look at the source code of full-mode bitcoin implementations in Java, such as bitsofproof (BOF).

It seems bitcoinj also has a full-mode but it is experimental only and not really suitable for prod.

Hope this helps...

Answer 2

You can use this blockchain link to get the balance

https://blockchain.info/q/getreceivedbyaddress/THEIRBITCOINADDRESS?confirmations=6

while you request it from the java

Answer 3

Using the bitcoinj Java library, you can retrieve your current balance very easily:

// To create your wallet.
public static NetworkParameters params = TestNet3Params.get();
public static String filePrefix = "forwarding-service-testnet";
public static WalletAppKit kit = new WalletAppKit(params, new File("."), filePrefix);

// to retrieve your balance.
String balance = kit.wallet().getBalance().toFriendlyString();
System.out.println(balance);