java BEP20交易监听 代码

以下是一个简单的Java代码示例，用于监听BEP20交易：

import org.web3j.abi.datatypes.Address;
import org.web3j.protocol.Web3j;
import org.web3j.protocol.core.DefaultBlockParameterName;
import org.web3j.protocol.core.methods.response.EthBlock;
import org.web3j.protocol.core.methods.response.Log;
import org.web3j.protocol.websocket.WebSocketService;
import org.web3j.tx.gas.DefaultGasProvider;
import org.web3j.utils.Numeric;

import java.math.BigInteger;
import java.util.List;

public class BEP20TransactionListener {

    private static final String CONTRACT_ADDRESS = "0x123456789abcdef";
    private static final String INFURA_ENDPOINT = "wss://rinkeby.infura.io/ws/v3/your-project-id";

    public static void main(String[] args) throws Exception {
        WebSocketService web3jService = new WebSocketService(INFURA_ENDPOINT, true);
        web3jService.connect();

        Web3j web3j = Web3j.build(web3jService);

        web3j.blockFlowable(false)
                .filter(block -> block.getBlock().getNumber().intValue() > 0)
                .subscribe(block -> {
                    List<EthBlock.TransactionResult> transactions = block.getBlock().getTransactions();
                    for (EthBlock.TransactionResult result : transactions) {
                        EthBlock.TransactionObject transaction = (EthBlock.TransactionObject) result.get();
                        if (transaction.getTo() != null && transaction.getTo().equals(CONTRACT_ADDRESS)) {
                            web3j.ethGetTransactionReceipt(transaction.getHash())
                                    .sendAsync()
                                    .thenAccept(receipt -> {
                                        List<Log> logs = receipt.getTransactionReceipt().getLogs();
                                        for (Log log : logs) {
                                            if (log.getTopics().get(0).equals("0xa9059cbb000000000000000000000000" + Numeric.cleanHexPrefix(transaction.getFrom()))) {
                                                String value = log.getData().substring(64);
                                                BigInteger amount = new BigInteger(value, 16);
                                                String token = new Address(log.getAddress()).toString();
                                                String from = new Address(Numeric.cleanHexPrefix(transaction.getFrom())).toString();
                                                String to = new Address(log.getTopics().get(2)).toString();
                                                System.out.println("Token: " + token);
                                                System.out.println("From: " + from);
                                                System.out.println("To: " + to);
                                                System.out.println("Amount: " + amount);
                                            }
                                        }
                                    });
                        }
                    }
                });
    }
}

这个代码示例使用了Web3j库，并连接到Infura节点。它通过订阅块流来监听交易，并过滤出发送到指定合约地址的交易。然后，它读取交易收据并解析出BEP20交易信息，包括交易的代币、发送者、接收者和数量。最后，它将这些信息打印到控制台上。

请注意，此代码示例并不完整，并可能需要根据您的具体需求进行更改。例如，您可能需要更改合约地址和节点端点。