思明自助建站软件营销培训讲师
题记
用Web3实现前端与智能合约的交互，以下是操作流程和代码。
准备ganache环境
文章地址：4.DApp-MetaMask怎么连接本地Ganache-CSDN博客
准备智能合约
文章地址： 2.DApp-编写和运行solidity智能合约-CSDN博客
编写index.html文件
<!DOCTYPE html>
<html>
<head>
<title>Name Contract Demo</title>
<!--导入web3库-->
<script src="https://cdn.jsdelivr.net/npm/web3@1.5.2/dist/web3.min.js"></script>
<script>
// 检查Metamask是否已安装
if (typeof window.ethereum !== 'undefined') {
console.log('Metamask已安装');
}
// 设置Web3.js提供者为Metamask
const provider = window.ethereum;
const web3 = new Web3(provider);
// 请求Metamask连接到以太坊网络
provider.request({ method: 'eth_requestAccounts' })
.then(() => {
console.log('Metamask已连接到以太坊网络');
})
.catch((err) => {
console.error('无法连接到以太坊网络', err);
});
function setName() {
// 合约地址
const contractAddress = '0x32FDC4E86421143b1c27dE49542Bc8ECE2B162a0';
// 合约ABI
const contractABI = [
{
"inputs": [
{
"internalType": "string",
"name": "_name",
"type": "string"
}
],
"name": "setName",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [],
"name": "getName",
"outputs": [
{
"internalType": "string",
"name": "",
"type": "string"
}
],
"stateMutability": "view",
"type": "function"
}
];
const contract = new web3.eth.Contract(contractABI, contractAddress);
const name = document.getElementById('name').value;
// 替换为您的账户地址web3.eth.defaultAccount
const fromAddress = '0x4e8eB4d1C203929074A3372F3703E556820fEA57';
//contract.methods.setName(name).send({from: fromAddress})
contract.methods.setName(name).send({from: fromAddress})
.on('transactionHash', function(hash){
console.log('Transaction Hash:', hash);
})
.on('receipt', function(receipt){
console.log('Transaction Receipt:', receipt);
})
.on('error', function(error){
console.error('Error:', error);
});
}
function getName() {
// 合约地址
const contractAddress = '0x32FDC4E86421143b1c27dE49542Bc8ECE2B162a0';
// 合约ABI
const contractABI = [
{
"inputs": [
{
"internalType": "string",
"name": "_name",
"type": "string"
}
],
"name": "setName",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [],
"name": "getName",
"outputs": [
{
"internalType": "string",
"name": "",
"type": "string"
}
],
"stateMutability": "view",
"type": "function"
}
];
const contract = new web3.eth.Contract(contractABI, contractAddress);
contract.methods.getName().call()
.then(function(result) {
console.log('Name:', result);
document.getElementById('nameValue').innerText = result;
})
.catch(function(error) {
console.error('Error:', error);
});
}
</script>
</head>
<body>
<h1>设置姓名</h1>
<label for="name">姓名:</label>
<input type="text" id="name">
<button οnclick="setName()">设置姓名</button>
<br>
<button οnclick="getName()">得到姓名</button>
<br>
<span id="nameValue"></span>
</body>
</html>
<!DOCTYPE html>
<html>
<head><title>Name Contract Demo</title><!--导入web3库--><script src="https://cdn.jsdelivr.net/npm/web3@1.5.2/dist/web3.min.js"></script><script>// 检查Metamask是否已安装if (typeof window.ethereum !== 'undefined') {console.log('Metamask已安装');}// 设置Web3.js提供者为Metamaskconst provider = window.ethereum;const web3 = new Web3(provider);// 请求Metamask连接到以太坊网络provider.request({ method: 'eth_requestAccounts' }).then(() => {console.log('Metamask已连接到以太坊网络');}).catch((err) => {console.error('无法连接到以太坊网络', err);});function setName() {// 合约地址const contractAddress = '0x32FDC4E86421143b1c27dE49542Bc8ECE2B162a0'; // 合约ABIconst contractABI = [{"inputs": [{"internalType": "string","name": "_name","type": "string"}],"name": "setName","outputs": [],"stateMutability": "nonpayable","type": "function"},{"inputs": [],"name": "getName","outputs": [{"internalType": "string","name": "","type": "string"}],"stateMutability": "view","type": "function"}]; const contract = new web3.eth.Contract(contractABI, contractAddress);const name = document.getElementById('name').value;// 替换为您的账户地址web3.eth.defaultAccountconst fromAddress = '0x4e8eB4d1C203929074A3372F3703E556820fEA57'; //contract.methods.setName(name).send({from: fromAddress})contract.methods.setName(name).send({from: fromAddress}).on('transactionHash', function(hash){console.log('Transaction Hash:', hash);}).on('receipt', function(receipt){console.log('Transaction Receipt:', receipt);}).on('error', function(error){console.error('Error:', error);});}function getName() {// 合约地址const contractAddress = '0x32FDC4E86421143b1c27dE49542Bc8ECE2B162a0'; // 合约ABIconst contractABI = [{"inputs": [{"internalType": "string","name": "_name","type": "string"}],"name": "setName","outputs": [],"stateMutability": "nonpayable","type": "function"},{"inputs": [],"name": "getName","outputs": [{"internalType": "string","name": "","type": "string"}],"stateMutability": "view","type": "function"}]; const contract = new web3.eth.Contract(contractABI, contractAddress);contract.methods.getName().call().then(function(result) {console.log('Name:', result);document.getElementById('nameValue').innerText = result;}).catch(function(error) {console.error('Error:', error);});}</script>
</head>
<body><h1>设置姓名</h1><label for="name">姓名:</label><input type="text" id="name"><button onclick="setName()">设置姓名</button><br><button onclick="getName()">得到姓名</button><br><span id="nameValue"></span>
</body>
</html>
执行程序
使用vscode的Live Server打开网页
参考这篇文章的执行方法：1.Vue-在独立页面实现Vue的增删改查-CSDN博客
展示图
发起交易
完成交易
后记
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