利用Java 发布智能合约:https://blog.csdn.net/Keith003/article/details/82744534
使用前需要将合约转换为java 代码 :https://blog.csdn.net/Keith003/article/details/81873154
如果没有搭建本地以太坊节点可以使用云客户端 infura :https://infura.io
连接以太坊网络
Web3j web3j = Web3j.build(new HttpService("以太坊节点地址"));
创建凭证
Credentials credentials = WalletUtils.loadCredentials("密码","Keystore文件地址");
获取当前gasPrice
public BigInteger getPrice(Web3j web3j) throws Exception{
EthGasPrice send = web3j.ethGasPrice().send();
BigInteger gasPrice = send.getGasPrice();
return gasPrice;
}
初始化合约
String contractAddress = "合约地址";
BigInteger gasPrice = getPrice(Web3j web3j);
BigInteger gasLimit = BigInteger.valueOf(80_000);
Contract erc20 = Contract.load(contractAddress, web3j, credentials, gasPrice, gasLimit );
注:这里GasLimit 设置为默认10KWei ,GasPrice 获取当前链上实时的GasPrice
调用合约方法:获取账户代币数量
RemoteCall balanceOf = erc20.balanceOf("以太坊账户地址");
CompletableFuture sendAsync = balanceOf.sendAsync();
System.out.println(sendAsync.get());
注:合约方法提供了send 同步方法和 sendAsync 异步方法 可根据具体需要选择
调用合约转账方法
BigInteger price = BigInteger.valueOf(10_000_000);
String to = "转到的账户地址";
RemoteCall transfer = erc20.transfer(to , price);
CompletableFuture sendAsync = transfer.sendAsync();
TransactionReceipt transactionReceipt = sendAsync.get();//返回交易信息
注:这里以太坊由于手续费不同可能打包的时间会不同 这里需要注意
还有很多接口这里就不一一列举了