本文主要是介绍以太坊day(3)，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

以太坊day （4）

• 一、遇见的错误
• • 1.1 Error: Invalid JSON RPC response:
• 二、goland上进行合约的开发
• • 2.1 需要的源
  • 2.2 合约文件
  • 2.3 编译合约
  • 2.4 部署合约
  • 2.5 获取合约实例
  • 2.6 与合约进行交互
  • 2.7 查看交易详细的应用
• 三、部署到真实的网络
• • 3.1 所需的数据
  • 3.2 服务商,infura
  • 3.3 安装依赖
  • 3.4 设置provider

一、遇见的错误

1.1 Error: Invalid JSON RPC response:

• 原因:端口号填错
  7545不是8545

web3.setProvider('HTTP://127.0.0.1:7545');

二、goland上进行合约的开发

2.1 需要的源

2.2 合约文件

pragma solidity ^0.4.26;
contract hello{
    string public name = "jack";
    function getName() public view returns (string){
        return name;
    }
    function steNamt(string myname) public {
        name = myname;
    }
}

2.3 编译合约

let solc = require('solc')
let fs = require('fs')
let sourcecode = fs.readFileSync('./contracts/helloname.sol','utf-8')
//console.log(sourcecode.toString())
let output = solc.compile(sourcecode, 1)
//console.log(output['contracts'])
module.exports = output['contracts'][':hello']

2.4 部署合约

let  {bytecode, interface} = require("./compile")
let Web3 = require("web3")
// console.log('bytecode:',bytecode)
// console.log('interface:',interface)
const account = "0xD5fFa32A808970FAb637AeE4ca70e00888B3e4D8"
let web3 = new Web3();
console.log("版本:",web3.version)
//1.设置网络
web3.setProvider('HTTP://127.0.0.1:7545');
//console.log(web3.providers)
//产看当前的currentProvider
//console.log(web3.currentProvider)
//2.拼接合约数据
let contract = new web3.eth.Contract(JSON.parse(interface))
//console.log("自己的contract:",contract)
web3.eth.defaultAccount = account;
//设置默认的账户
console.log(web3.eth.defaultAccount)
console.log(contract.defaultBlock)
// //3.拼接bytecode
contract.deploy({
    data:bytecode,
    arguments: ["success"]
})
    .send({
        from: account,
        gas: 5721975,
        gasPrice: '300000000000'
    })
    .then(function(newContractInstance){
        //newContractInstance.options.address 得到的是新的合约的地址
        console.log(newContractInstance.options.address) // instance with the new contract address
    });

2.5 获取合约实例

//获取合约实例
let Web3 = require('web3')
let web3 = new Web3()
let {bytecode, interface} = require('./compile')
let contractAddress = require('./deploy')
console.log(interface)
console.log(contractAddress)
//根据api和address得到合约实例
let contracInstance = new web3.eth.Contract(JSON.parse(interface), contractAddress)
console.log(contracInstance)

2.6 与合约进行交互

//1.获取合约实例
let contractInstance = require('./instance')
const from = '0xC8147B0093339470dA5aaF4DFF643815c4adA893'
contractInstance.methods.getName().call().then(result =>{
    //1.读取到合约的结果
    console.log("得到的结果:",result)
    //2.设置合约的变量值
    contractInstance.methods.setName("currentJack").send({
        from:from,
        value:0}).then(res =>{
            console.log(res)
        //3.得到新的合约的值
        contractInstance.methods.getName().call().then(res=>{
            console.log("得到修改后的结果", res)
        })
    })
})

2.7 查看交易详细的应用

ganache

进去后点quick start

三、部署到真实的网络

3.1 所需的数据

• 助记词，花费谁的钱
• 服务商，帮助我们连接到真实的网络
  infura
• npm包，接受两个参数，然后帮我们链接到对应的网络
  npm install truffle-hdwallet-provider

3.2 服务商,infura

• 记得选择ropsten

3.3 安装依赖

• npm install truffle-hdwallet-provider

3.4 设置provider

//1.合约的地址
let Web3 = require('web3')
let contractAddres = "合约的地址"
let {bytecode,interface} = require('./compile')
//console.log("得到的interface",interface)
let web3 = new Web3()
let THP = require('truffle-hdwallet-provider')
let terms = '账户的助记词'
//2.得到服务商网址
let netip = 'infura创建的项目的url'
let provider = new THP(terms, netip)
web3.setProvider(provider)
//console.log(web3.currentProvider)
//3.根据合约地址和api得到合约的实例
let contractInstance = new web3.eth.Contract(JSON.parse(interface),contractAddres)
//console.log("合约的实例",contractInstance)
module.exports = contractInstance

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