springboot操作以太坊（eth），使用web3j，转账等

开发以太坊prc客户端：

本次使用的是《metaMask》钱包

1，安装node.js

2，安装ganache-cli，开启本地web3j的测试服务

安装命令：npm install -g ganache-cli

启动本地服务命令：ganache-cli -i 1 -h 0.0.0.0 -p 8545

启动成功同时生成是个测试账号，每个账号100eth，如图

然后再metaMask钱包可以通过输入秘钥的方式添加账号，如图

3.springboot部分：

导入pom     
            org.web3j
            core
            5.0.0
        

如果运行报错 (okhttp3.RequestBody.create(Ljava/lang/String；Lokhttp3/MediaType；)Lokhttp3/RequestBody)则添加pom

 
            com.squareup.okhttp3
            okhttp
            4.3.1
       

创建web3j对象：

Web3j web3 = Web3j.build(new HttpService("http://localhost:8545/"));

4，已有metamask钱包的情况，没有metamask钱包，请先申请账号

public static void trade(Web3j web3) {
		try {
			//根据私钥创建身份信息
			Credentials credentials = Credentials.create("0xa91514e0c5f1d5929b3052b756d07a0123ec5cf7b86188f4410033bdc99a85e7");
			//转账
			TransactionReceipt transactionReceipt = Transfer.sendFunds(
					web3, credentials, "0xb425cEA579C1c2F7A902ec1aFB5d2bEE04A611eA",
					BigDecimal.valueOf(1.0), Convert.Unit.ETHER).send();
			
			System.out.println(transactionReceipt.getBlockHash());
		} catch (IOException | CipherException e) {
			e.printStackTrace();
		} catch (InterruptedException e) {
			e.printStackTrace();
		} catch (TransactionException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}
		
	}
	

5，使用代码创建钱包

创建：

public static void createWallet() {
		//存放钱包的位置，不需要文件名，会自动生成
		String filePath = "G:/eth_wallet";
		File f = new File(filePath);
		try {//"l.1061326670"你钱包的密码
			String fileName = WalletUtils.generateNewWalletFile("l.1061326670", f , false);
			System.out.println(fileName);
			Credentials credentials = WalletUtils.loadCredentials("l.1061326670", f);
			System.out.println(credentials.getAddress());//钱包地址
			System.out.println(credentials.getEcKeyPair().getPrivateKey());//私钥
			System.out.println(credentials.getEcKeyPair().getPublicKey());//公钥
		} catch (CipherException | IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InvalidAlgorithmParameterException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (NoSuchProviderException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		
	}

转账：

public static void tradeByonlineWallet(Web3j web3) {
		try {
			String filePath = "G:/eth_wallet/***.json";
			File f = new File(filePath);
			Credentials credentials = WalletUtils.loadCredentials("l.1061326670", f);
			TransactionReceipt transactionReceipt = Transfer.sendFunds(
					web3, credentials, "0xb425cEA579C1c2F3A024ec1aFB5d2bEE04A611eA",
					BigDecimal.valueOf(1.0), Convert.Unit.ETHER).send();
			
			System.out.println(transactionReceipt.getBlockHash());
		} catch (IOException | CipherException e) {
			e.printStackTrace();
		} catch (InterruptedException e) {
			e.printStackTrace();
		} catch (TransactionException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}
		
	}