Java连接比特币公共测试节点地址

本文将介绍如何使用Java连接比特币公共测试节点地址，并提供代码示例。

一、连接比特币公共测试节点

比特币公共测试节点是一种用于测试或学习比特币开发的节点，使用公共测试节点可以避免需要自行搭建节点的麻烦。Java连接比特币公共测试节点的方式可以分为两种。

1. 使用Java开源库bitcoinj连接测试节点

bitcoinj是一个开源库，提供了Java连接比特币网络的工具。我们可以使用以下代码连接比特币公共测试节点。

NetworkParameters testNetParams = TestNet3Params.get();
String testNetHost = "testnet.test";
int testNetPort = 18333;
String testNetUser = "test";
String testNetPassword = "test";

try {
    //连接测试节点
    BlockChain blockChain = new BlockChain(testNetParams, new PeerAddress(InetAddress.getByName(testNetHost), testNetPort));
    BlockStore blockStore = new MemoryBlockStore(testNetParams);
    Wallet wallet = new Wallet(testNetParams);
    BlockChainListener listener = new MyBlockChainListener(wallet);

    blockChain.addListener(listener);
    PeerGroup peerGroup = new PeerGroup(testNetParams, blockChain);
    peerGroup.addPeer(new Peer(testNetParams, new VersionMessage(testNetParams, 0), new PeerAddress(InetAddress.getByName(testNetHost), testNetPort)));
    peerGroup.addWallet(wallet);
    peerGroup.start();
} catch (Exception e) {
    e.printStackTrace();
}

2. 通过Java连接比特币公共测试节点RPC方法

除了使用bitcoinj，我们还可以通过Java连接比特币公共测试节点的RPC方法，具体方法如下：

String rpcuser = "test";
String rpcpassword = "test";
String rpcIP = "testnet.test";
String rpcPort = "18332";

//设置认证信息
Authenticator.setDefault(new Authenticator() {
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication(rpcuser, 
      rpcpassword.toCharArray());
    }
});

//建立连接
try {
    URL url = new URL("http://" + rpcIP + ":" + rpcPort + "/");
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    connection.setDoOutput(true);
    connection.setRequestMethod("POST");

    //发送请求
    String jsonReq = "{"jsonrpc":"1.0","id":"curltext","method":"getinfo","params":[]}";
    OutputStreamWriter wr = new OutputStreamWriter(connection.getOutputStream());
    wr.write(jsonReq);
    wr.flush();

    //读取响应
    BufferedReader rd = new BufferedReader(new InputStreamReader(connection.getInputStream()));
    String line;
    while ((line = rd.readLine()) != null) {
        System.out.println(line);
    }
    wr.close();
    rd.close();

} catch (Exception e) {
    e.printStackTrace();
}

二、比特币操作

连接比特币公共测试节点后，我们可以通过Java进行比特币操作，比如获取比特币余额、发送比特币等操作。

1. 获取比特币余额

我们可以通过以下代码获取当前账户的比特币余额。

String rpcuser = "test";
String rpcpassword = "test";
String rpcIP = "testnet.test";
String rpcPort = "18332";

Authenticator.setDefault(new Authenticator() {
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication(rpcuser, rpcpassword.toCharArray());
    }
});

try {
    //查询余额
    URL url = new URL("http://" + rpcIP + ":" + rpcPort + "/");
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    connection.setDoOutput(true);
    connection.setRequestMethod("POST");
    String jsonReq = "{"jsonrpc":"1.0","id":"curltext","method":"getbalance","params":["" + account + ""]}";
    OutputStreamWriter wr = new OutputStreamWriter(connection.getOutputStream());

    wr.write(jsonReq);
    wr.flush();

    BufferedReader rd = new BufferedReader(new InputStreamReader(connection.getInputStream()));
    String line;
    while ((line = rd.readLine()) != null) {
        System.out.println(line);
    }
    wr.close();
    rd.close();

} catch (Exception e) {
    e.printStackTrace();
}

2. 发送比特币

发送比特币需要构造一个交易交易的输入和输出，以下是一个简单的示例代码。

String rpcuser = "test";
String rpcpassword = "test";
String rpcIP = "testnet.test";
String rpcPort = "18332";

Authenticator.setDefault(new Authenticator() {
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication(rpcuser, rpcpassword.toCharArray());
    }
});

try {
    //构造交易输入
    TransactionInput input = new TransactionInput(params, null, new byte[] {}, new TransactionOutPoint(params, 0, Sha256Hash.wrap(fromTxHash)));
    input.setScriptSig(ScriptBuilder.createInputScript(wallet.getKeys().get(0), wallet.getKeys().get(0).getPubKey()));

    //构造交易输出
    Address to = new Address(params, toAddress);
    Coin value = Coin.parseCoin(valueStr);
    TransactionOutput output = new TransactionOutput(params, null, to, value);

    //构造交易
    Transaction tx = new Transaction(params);
    tx.addInput(input);
    tx.addOutput(output);

    //签名交易
    wallet.signTransaction(Sha256Hash.wrap(tx.getHash()), tx.getInput(0).getScriptSig(), wallet.getKeys().get(0), SigHash.ALL, true);
    System.out.println(tx);

    //发送交易
    String hexString = Hex.encodeHexString(tx.bitcoinSerialize()).toUpperCase();
    URL url = new URL("http://" + rpcIP + ":" + rpcPort + "/");
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    connection.setDoOutput(true);
    connection.setRequestMethod("POST");
    String jsonReq = "{"jsonrpc":"1.0","id":"curltext","method":"sendrawtransaction","params":["" + hexString + ""]}";
    OutputStreamWriter wr = new OutputStreamWriter(connection.getOutputStream());

    wr.write(jsonReq);
    wr.flush();

    BufferedReader rd = new BufferedReader(new InputStreamReader(connection.getInputStream()));
    String line;
    while ((line = rd.readLine()) != null) {
        System.out.println(line);
    }
    wr.close();
    rd.close();

} catch (Exception e) {
    e.printStackTrace();
}

三、总结

本文介绍了使用Java连接比特币公共测试节点的两种方法，并提供了获取比特币余额和发送比特币的代码示例，希望能够对读者有所帮助。