web3入门-web3.js通过Ganache连接truffle智能合约_truffle与web3.js

//环境
Truffle v5.5.21 (core: 5.5.21)
Ganache v7.2.0
Solidity v0.5.16 (solc-js)
Node v14.17.3
Web3.js v1.7.4

一、用truffle框架在本地部署智能合约

1.建个文件夹 truffle_demo

mkdir truffle_demo

2.进入文件夹内，执行init命令，会搭建基本框架出来

truffle init

3.在contracts下新建一个文件，比如DataDemo.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.4.22 <0.9.0;
contract DataDemo{
    string public returnTest;
    //set方法
    function setData(string memory str ) public payable {
        returnTest = str;
    }
    //get方法
    function getData() public view returns (string memory) {
        return returnTest;
    }
}

4.修改migrations/1_initial_migration.js

const Migrations = artifacts.require("Migrations");
var DataDemo = artifacts.require("./DataDemo.sol");
 
module.exports = function(deployer) {
  deployer.deploy(Migrations);
  d