NFT質押借貸（馬蹄鏈）系統設計開發分析丨DAPP丨DeFi丨NFT

NFT質押借貸是一種將非同質化代幣（NFT）與借貸市場結合的新型金融應用，允許NFT持有者使用其資產作為質押品來獲取貸款或直接借出NFT以獲得收益。這種新型金融應用可以為NFT持有者提供更多的資金使用方式和流動性，同時也可以促進NFT市場的發展。

基於以太坊區塊鏈的NFT質押借貸合約的示例程式碼：

csharpCopy codepragma solidity ^0.8.0;
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
contract NFTLoan is IERC721Receiver, Ownable {    struct NFT {
        uint256 id;
        address owner;
        uint256 value;
    }
    mapping(address => mapping(uint256 => NFT)) private nfts;
    mapping(address => uint256) private balances;
    mapping(address => uint256) private loanAmounts;
    IERC20 private token;
    uint256 private interestRate;
    uint256 private nftCounter;    event NFTDeposited(address indexed owner, uint256 indexed id);    event NFTWithdrawn(address indexed owner, uint256 indexed id);    event LoanRequested(address indexed borrower, uint256 amount);    event LoanPaid(address indexed borrower, uint256 amount);    event CollateralWithdrawn(address indexed owner, uint256 amount);
    constructor(address _token, uint256 _interestRate) {
        token = IERC20(_token);
        interestRate = _interestRate;
        nftCounter = 0;
    }    function depositNFT(address _nft, uint256 _id) public {
        IERC721 nft = IERC721(_nft);
        nft.safeTransferFrom(msg.sender, address(this), _id);
        nfts[_nft][_id] = NFT(nftCounter, msg.sender, 0);
        nftCounter += 1;        emit NFTDeposited(msg.sender, nftCounter - 1);
    }    function withdrawNFT(address _nft, uint256 _id) public {
        NFT storage nft = nfts[_nft][_id];
        require(nft.owner == msg.sender, "You do not own this NFT");
        IERC721(_nft).safeTransferFrom(address(this), msg.sender, _id);
        delete nfts[_nft][_id];        emit NFTWithdrawn(msg.sender, nft.id);
    }    function requestLoan(uint256 _amount) public {
        require(token.balanceOf(address(this)) >= _amount, "Insufficient funds");
        token.transfer(msg.sender, _amount);
        loanAmounts[msg.sender] += _amount;        emit LoanRequested(msg.sender, _amount);
    }    function repayLoan(uint256 _amount) public {
        require(token.allowance(msg.sender, address(this)) >= _amount, "Insufficient allowance");
        require(token.balanceOf(msg.sender) >= _amount, "Insufficient balance");
        token.transferFrom(msg.sender, address(this), _amount);
        loanAmounts[msg.sender] -= _amount;
        emit Loan