区块链学习之Web3j入门（五）: 裸交易的实现

1.裸交易的过程

与普通交易由节点负责签名不同，裸交易需要外部应用进行离线签名。 因此在使用裸交易之前，需要首先载入账户凭证，利用私钥进行签名。

2.裸交易的实现

从账户一向账户九转账1个以太币，流程如下：首先创建账户一的凭证对象，然后创建交易请求，再用账户一的凭证对该请求进行签名，签名结束最后提交该交易请求即完成一次裸交易。

    @Test
    public void submitRawTransaction() throws IOException, CipherException, ExecutionException, InterruptedException {
        Web3j web3j = Web3j.build(new HttpService("http://localhost:8545"));
        Credentials credentials = Credentials.create("0x355321e6df9ae014b0e19d2d49db10508e3b717326a925cd282896114ad26922");//通过账户1的私钥创建凭证对象
        List<String> accounts = web3j.ethAccounts().send().getAccounts();
        String to = accounts.get(8);
        BigInteger gasPrice =  BigInteger.valueOf(22000000000L);
        BigInteger gasLimit =  BigInteger.valueOf(670000);
        BigInteger value = Convert.toWei("1",Convert.Unit.ETHER).toBigInteger();
        String data = "";
        BigInteger nonce = web3j.ethGetTransactionCount(credentials.getAddress(),DefaultBlockParameterName.LATEST).send().getTransactionCount();
        RawTransaction transaction = RawTransaction.createTransaction(nonce, gasPrice, gasLimit, to,value,data);//准备好transaction对象
        byte[] signMessage = TransactionEncoder.signMessage(transaction, credentials);//利用账户凭证进行签名，得到字节流签名信息
        String hexMessage = Numeric.toHexString(signMessage); //将字节流转换为十六进制字符串
        String transactionHash = web3j.ethSendRawTransaction(hexMessage).send().getTransactionHash();//请求交易
        System.out.println("nonce:"+nonce);
        System.out.println("transactionHash:"+transactionHash);
        System.out.println("transaction:"+transaction);
        System.out.println("hexMessage:"+hexMessage);
        BigInteger toBalance = web3j.ethGetBalance(to,DefaultBlockParameterName.LATEST).send().getBalance();
        System.out.println("账户9余额:"+toBalance);
    }
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