1. ERC20標準

https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md

pragma solidity ^0.4.4;//定義接口 contract ERC20Interface{string public name;string public symbol;uint8 public decimals;uint256 public totalSupply;/* function balanceOf(address _owner) view returns (uint256 balance); */function transfer(address _to, uint256 _value) returns (bool success);function transferFrom(address _from, address _to, uint256 _value) returns (bool success);function approve(address _spender, uint256 _value) returns (bool success);function allowance(address _owner, address _spender) view returns (uint256 remaining);event Transfer(address indexed _from, address indexed _to, uint256 _value);event Approval(address indexed _owner, address indexed _spender, uint256 _value);}contract ERC20 is ERC20Interface{mapping(address => uint256) public balanceOf;//委托，允許他人操作的金額數mapping(address => mapping(address => uint256)) allowed;//構造方法constructor() public {name = "MyToken";symbol = "weixuexi";decimals = 0;totalSupply = 10000;balanceOf[msg.sender] = totalSupply;}/* function balanceOf(address _owner) view returns (uint256 balance){return balanceOf[_owner];} */function transfer(address _to, uint256 _value) returns (bool success){require(_to != address(0));require(balanceOf[msg.sender] >= _value);require(balanceOf[_to] + _value > balanceOf[_to]);balanceOf[msg.sender] -= _value;balanceOf[_to] += _value;emit Transfer(msg.sender, _to, _value);}function transferFrom(address _from, address _to, uint256 _value) returns (bool success){require(_from != address(0));require(_to != address(0));require(balanceOf[_from] >= _value);require(allowed[msg.sender][_from] >= _value); //當前合約能操作_from的錢數要大于_valuerequire(balanceOf[_to] + _value > balanceOf[_to]);balanceOf[_from] -= _value;balanceOf[_to] += _value;emit Transfer(_from, _to, _value);success = true;}function approve(address _spender, uint256 _value) returns (bool success){//當前賬戶允許—_spender操作的金額數allowed[msg.sender][_spender] = _value;emit Approval(msg.sender, _spender, _value);success = true;}function allowance(address _owner, address _spender) view returns (uint256 remaining){return allowed[_owner][_spender];} } View Code

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?2.DAPP去中心化應用開發【web項目】

　　web3.js

　　solidity

　　truffle??https://truffleframework.com/docs/truffle/getting-started/installation

　　ganache

開發流程：

• 新建項目【初始化】
• 編寫合約
• 合約編譯、部署、測試
• 與合約交互

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安裝truffle：

npm install -g truffle
查看版本：truffle.cmd version

創建項目：

　　下載基本文件：

　　 　? cd pet-shop

　　　　truffle init? 【安裝項目】

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　　下載pet-shop包文件：

　　　　cd pet-shop

　　truffle unbox pet-shop

?編寫智能合約：Adoption.sol

pragma solidity ^0.4.23;contract Adoption {address[16] public adoptors; //領養這地址 function adopt(uint petId) public returns(uint) {adoptors[petId] = msg.sender;return petId;}function getAdoptors() public view returns (address[16]) {return adoptors;} }

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編譯： truffle.cmd compile【方式一，結合使用ganache】

　　truffle develop 【方式二，truffle集成了testrpc】； compile;

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部署合約：migrate

　　部署合約腳本： 1_migration.js? ?改文件用于監聽合約文件的動向，是否更新，變化

var MyContract = artifacts.require("MyContract");module.exports = function(deployer) {// deployment steps deployer.deploy(MyContract); };

?　　truffle.js:

module.exports = {// See <http://truffleframework.com/docs/advanced/configuration>// to customize your Truffle configuration! networks: {development: {host: "127.0.0.1", //主機port: 7545, //端口，和ganache對應network_id: "*" // Match any network id }} };

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　　部署合約：[truffle] migrate

輸出結果：Adoption.json? [編譯出的文件做出了更新]

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?這時，ganache中可以發現，已經出來了4個區塊：

還有交易信息：

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?獲取合約實例，調用函數：

pragma solidity ^0.4.23;contract Hello {//如果使用pure修飾，可以通過合約對象直接調用，否則需要使用call方法調用function test() pure public returns (string) {return "hello world";} } Hello.sol

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/migrations/3_deploy_hello.js

var Hello = artifacts.require("./Hello.sol");module.exports = function(deployer) {deployer.deploy(Hello); };

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　　使用web3獲取合約實例：　

>truffle:　let contract;? ?//聲明contract變量

　　　　contract = Hello.deployed().then(instance => contract=instance)? ? ? ? ? ? ?//Hello 是上面遷移文件的合約實例

pragma solidity ^0.4.23;import "truffle/Assert.sol"; import "truffle/DeployedAddresses.sol"; import "../contracts/Adoption.sol";contract TestAdoption {Adoption adoption = Adoption(DeployedAddresses.Adoption());function testUserCatAdoptPet() public {uint returnId = adoption.adopt(8);uint expect = 8;Assert.equal(returnId, expect, "Adoption of pet Id 8 should be recorded");}function testGetAdoptorAddByPetId() public {address expect = this;address adoptor = adoption.adoptors(8);Assert.equal(expect, adoptor, "get adopt by pet id");} } View Code

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　　注意：修改完合約文件后，重新編譯【compile】后，重新部署命令【migrate --reset】

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　　調用合約方法：contract.test();

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?　　使用斷言測試：Assert

同時會多出很多新的區塊和交易

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?3.web3.js api的使用

官網

　　進入truffle開發環境：truffle.cmd develop

　　獲取賬戶余額：web3.eth.getBalace("").toString();

truffle(develop)> web3.eth.getBalance("0x627306090abab3a6e1400e9345bc60c78a8bef57").toString()'100000000000000000000'

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　　獲取所有賬戶：web3.eth.accounts;

truffle(develop)> null [ '0x627306090abab3a6e1400e9345bc60c78a8bef57','0xf17f52151ebef6c7334fad080c5704d77216b732','0xc5fdf4076b8f3a5357c5e395ab970b5b54098fef','0x821aea9a577a9b44299b9c15c88cf3087f3b5544','0x0d1d4e623d10f9fba5db95830f7d3839406c6af2','0x2932b7a2355d6fecc4b5c0b6bd44cc31df247a2e','0x2191ef87e392377ec08e7c08eb105ef5448eced5','0x0f4f2ac550a1b4e2280d04c21cea7ebd822934b5','0x6330a553fc93768f612722bb8c2ec78ac90b3bbc','0x5aeda56215b167893e80b4fe645ba6d5bab767de' ]

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　　獲取當前賬號：【數組中的第0個賬號】

truffle(develop)> web3.eth.coinbase;'0x627306090abab3a6e1400e9345bc60c78a8bef57'

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?　　web3.fromWei(num, 單位);

truffle(develop)> web3.fromWei(5, 'ether')'0.000000000000000005'

　　web3.toWei(num,單位)

　　默認的區塊：

truffle(develop)> web3.eth.defaultBlock'latest'

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　　交易：

truffle(develop)> web3.eth.sendTransaction({from:account1, to:account2, value:100000000000000000})'0xb5065a9a03d75f08d7e704d352d08de5c8c4f8f19cc654cb1261d254f6194d90' truffle(develop)> web3.eth.getBalance(account1)BigNumber { s: 1, e: 19, c: [ 998999, 99999999979000 ] } truffle(develop)> web3.eth.getBalance(account2)BigNumber { s: 1, e: 20, c: [ 1001000 ] } truffle(develop)> web3.eth.getBalance(account1).toString()'99899999999999979000' truffle(develop)> web3.eth.getBalance(account2).toString()'100100000000000000000' truffle(develop)> web3.fromWei(web3.eth.getBalance(account1).toString(), 'ether')'99.899999999999979' truffle(develop)> web3.fromWei(web3.eth.getBalance(account2).toString(), 'ether')'100.1' truffle(develop)> web3.fromWei(web3.eth.getBalance(web3.eth.accounts[2]).toString(), 'ether')'100'

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4. 代幣合約的概念

pragma solidity ^0.4.4;contract EncryptedToken {uint256 INITAL_SUPPLY = 10000;mapping(address => uint) public balanceOf;constructor() {balanceOf[msg.sender] = INITAL_SUPPLY;}function transfer(address _to, uint256 _value) public {require(_to != address(0));require(balanceOf[msg.sender] >= _value);require(balanceOf[_to] + _value > balanceOf[_to]);balanceOf[msg.sender] -= _value;balanceOf[_to] += _value;} } EncryptedToken.sol

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var EncryptedToken = artifacts.require("./EncryptedToken.sol");module.exports = function(deployer) {deployer.deploy(EncryptedToken); }; 1_deploy_encryptedToken.js

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部署：

　　truffle.cmd develop

　　compile

　　migate

　　let c;

　　EncryptedToken.deployed().then(inc => c=inc);

　　c.balanceOf("0x627306090abab3a6e1400e9345bc60c78a8bef57") ;? ->10000? ?//錢包地址

默認部署到第一個測試錢包中：

轉賬：c.transfer("0xf17f52151ebef6c7334fad080c5704d77216b732",1000)

truffle(develop)> c.balanceOf("0x627306090abab3a6e1400e9345bc60c78a8bef57")
　　　　　　　BigNumber { s: 1, e: 3, c: [ 9000 ] }

5. web端

4.1 使用npm管理項目

　　npm init

　　安裝web server：npm install lite-server

配置文件：bs-config.json

{"server" : {"baseDir":["./src", "./build/contracts"]} }

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package.json:

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啟動服務：npm run dev

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轉載于:https://www.cnblogs.com/zhuxiang1633/p/9486914.html

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