什么是DeFi (去中心化金融)

DeFi (去中心化金融) 概述 💰

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1. DeFi 基础概念

1.1 什么是 DeFi？

DeFi 是建立在区块链上的金融服务生态系统，它：

无需中心化中介
开放且透明
无需许可即可参与
代码即法律

1.2 DeFi 的优势

开放性：任何人都可以参与
透明性：所有交易公开可查
自动化：智能合约执行
可组合性：“金融乐高”

2. DeFi 核心协议类型

2.1 去中心化交易所（DEX）

// Uniswap V2 风格的 DEX 示例
contract SimpleDEX {mapping(address => mapping(address => uint)) public reserves;function addLiquidity(address tokenA, address tokenB, uint amountA, uint amountB) external {require(amountA > 0 && amountB > 0, "Invalid amounts");reserves[tokenA][tokenB] += amountA;reserves[tokenB][tokenA] += amountB;}function getPrice(address tokenA, address tokenB) public view returns (uint) {return reserves[tokenA][tokenB] / reserves[tokenB][tokenA];}
}

2.2 借贷协议

contract SimpleLending {mapping(address => uint) public deposits;mapping(address => uint) public borrows;function deposit() external payable {deposits[msg.sender] += msg.value;}function borrow(uint amount) external {require(amount <= deposits[msg.sender] * 2, "Insufficient collateral");borrows[msg.sender] += amount;}
}

3. DeFi 生态系统

3.1 主要协议

DEX
- Uniswap
- SushiSwap
- Curve
借贷平台
- Aave
- Compound
- MakerDAO
收益聚合器
- Yearn Finance
- Convex
- Harvest

3.2 基础设施

// Web3 连接示例
const connectDeFi = async () => {const provider = new ethers.providers.Web3Provider(window.ethereum);const signer = provider.getSigner();// 连接到 Aave 协议const lendingPool = new ethers.Contract(AAVE_LENDING_POOL_ADDRESS,LENDING_POOL_ABI,signer);// 获取用户数据const userAccountData = await lendingPool.getUserAccountData(userAddress);return userAccountData;
};

4. DeFi 交互模式

4.1 流动性提供

interface IUniswapV2Router {function addLiquidity(address tokenA,address tokenB,uint amountADesired,uint amountBDesired,uint amountAMin,uint amountBMin,address to,uint deadline) external returns (uint amountA, uint amountB, uint liquidity);
}

4.2 收益耕作

contract YieldFarming {IERC20 public stakingToken;IERC20 public rewardToken;mapping(address => uint) public stakedBalance;mapping(address => uint) public rewardBalance;function stake(uint amount) external {stakingToken.transferFrom(msg.sender, address(this), amount);stakedBalance[msg.sender] += amount;}function claimRewards() external {uint reward = calculateReward(msg.sender);rewardToken.transfer(msg.sender, reward);}
}

5. 风险管理

5.1 智能合约风险

contract SafeDeFi {// 紧急停止bool public paused;modifier whenNotPaused() {require(!paused, "Contract is paused");_;}// 限额控制uint public maxDeposit = 1000 ether;modifier withinLimit(uint amount) {require(amount <= maxDeposit, "Exceeds deposit limit");_;}// 重入锁bool private locked;modifier noReentrant() {require(!locked, "No reentrancy");locked = true;_;locked = false;}
}

5.2 价格操纵防护

contract PriceOracle {function getPrice(address token) external view returns (uint) {// 使用时间加权平均价格（TWAP）uint[] memory prices = getHistoricalPrices(token, 24 hours);return calculateTWAP(prices);}function calculateTWAP(uint[] memory prices) internal pure returns (uint) {// 计算加权平均价格uint sum = 0;for (uint i = 0; i < prices.length; i++) {sum += prices[i];}return sum / prices.length;}
}

6. DeFi 开发工具

6.1 开发框架

// 使用 Hardhat 部署 DeFi 协议
async function deployProtocol() {// 部署代币const Token = await ethers.getContractFactory("Token");const token = await Token.deploy();// 部署 DEXconst DEX = await ethers.getContractFactory("DEX");const dex = await DEX.deploy(token.address);// 部署收益耕作const Farm = await ethers.getContractFactory("Farm");const farm = await Farm.deploy(token.address, dex.address);return { token, dex, farm };
}

6.2 测试工具

describe("DeFi Protocol", function() {it("Should provide liquidity", async function() {const { token, dex } = await deployProtocol();// 添加流动性await token.approve(dex.address, ethers.utils.parseEther("1000"));await dex.addLiquidity(ethers.utils.parseEther("1000"),{ value: ethers.utils.parseEther("10") });// 验证流动性const reserves = await dex.getReserves();expect(reserves.token).to.equal(ethers.utils.parseEther("1000"));expect(reserves.eth).to.equal(ethers.utils.parseEther("10"));});
});