任何人都可以编写智能合约并将其部署到区块链网络上。 您只需要学习如何用智能合约语言编码，并有足够的以太币来部署您的合约。 部署智能合约在技术上是一笔交易，因此就像你需要为简单的以太币转账支付燃料费一样，你也需要为部署智能合约支付燃料费。 但是，合约部署的燃料成本要高得多。
以太坊提供对开发者友好的智能合约编程语言：
Solidity Vyper
然而，智能合约必须要先编译才能部署，以便以太坊虚拟机可以解释并存储它们。
代码语言：javascript复制contract BlackList is Ownable, BasicToken { /// Getters to allow the same blacklist to be used also by other contracts (including upgraded Tether) ///
function getBlackListStatus(address _maker) external constant returns (bool) { return isBlackListed[_maker];
} function getOwner() external constant returns (address) { return owner;
}
mapping (address => bool) public isBlackListed;
function addBlackList (address _evilUser) public onlyOwner {
isBlackListed[_evilUser] = true;
AddedBlackList(_evilUser);
} function removeBlackList (address _clearedUser) public onlyOwner {
isBlackListed[_clearedUser] = false;
RemovedBlackList(_clearedUser);
} function destroyBlackFunds (address _blackListedUser) public onlyOwner {
require(isBlackListed[_blackListedUser]); uint dirtyFunds = balanceOf(_blackListedUser);
balances[_blackListedUser] = 0;
_totalSupply -= dirtyFunds;
DestroyedBlackFunds(_blackListedUser, dirtyFunds);
} event DestroyedBlackFunds(address _blackListedUser, uint _balance); event AddedBlackList(address _user); event RemovedBlackList(address _user);
}
contract UpgradedStandardToken is StandardToken{ // those methods are called by the legacy contract
// and they must ensure msg.sender to be the contract address
function transferByLegacy(address from, address to, uint value) public; function transferFromByLegacy(address sender, address from, address spender, uint value) public; function approveByLegacy(address from, address spender, uint value) public;
}
contract TetherToken is Pausable, StandardToken, BlackList { string public name; string public symbol; uint public decimals;
address public upgradedAddress; bool public deprecated; // The contract can be initialized with a number of tokens
// All the tokens are deposited to the owner address
//
// @param _balance Initial supply of the contract
// @param _name Token Name
// @param _symbol Token symbol
// @param _decimals Token decimals
function TetherToken(uint _initialSupply, string _name, string _symbol, uint _decimals) public {
_totalSupply = _initialSupply;
name = _name;
symbol = _symbol;
decimals = _decimals;
balances[owner] = _initialSupply;
deprecated = false;
} // Forward ERC20 methods to upgraded contract if this one is deprecated
function transfer(address _to, uint _value) public whenNotPaused {
require(!isBlackListed[msg.sender]); if (deprecated) { return UpgradedStandardToken(upgradedAddress).transferByLegacy(msg.sender, _to, _value);
} else { return super.transfer(_to, _value);
}
} // Forward ERC20 methods to upgraded contract if this one is deprecated
function transferFrom(address _from, address _to, uint _value) public whenNotPaused {
require(!isBlackListed[_from]); if (deprecated) { return UpgradedStandardToken(upgradedAddress).transferFromByLegacy(msg.sender, _from, _to, _value);
} else { return super.transferFrom(_from, _to, _value);
}
} // Forward ERC20 methods to upgraded contract if this one is deprecated
function balanceOf(address who) public constant returns (uint) { if (deprecated) { return UpgradedStandardToken(upgradedAddress).balanceOf(who);
} else { return super.balanceOf(who);
}
} // Forward ERC20 methods to upgraded contract if this one is deprecated
function approve(address _spender, uint _value) public onlyPayloadSize(2 * 32) { if (deprecated) { return UpgradedStandardToken(upgradedAddress).approveByLegacy(msg.sender, _spender, _value);
} else { return super.approve(_spender, _value);
}
} // Forward ERC20 methods to upgraded contract if this one is deprecated
function allowance(address _owner, address _spender) public constant returns (uint remaining) { if (deprecated) { return StandardToken(upgradedAddress).allowance(_owner, _spender);
} else { return super.allowance(_owner, _spender);
}
} // deprecate current contract in favour of a new one
function deprecate(address _upgradedAddress) public onlyOwner {
deprecated = true;
upgradedAddress = _upgradedAddress;
Deprecate(_upgradedAddress);
} // deprecate current contract if favour of a new one
function totalSupply() public constant returns (uint) { if (deprecated) { return StandardToken(upgradedAddress).totalSupply();
} else { return _totalSupply;
}
} // Issue a new amount of tokens
// these tokens are deposited into the owner address
//
// @param _amount Number of tokens to be issued
function issue(uint amount) public onlyOwner {
require(_totalSupply amount > _totalSupply);
require(balances[owner] amount > balances[owner]);
balances[owner] = amount;
_totalSupply = amount;
Issue(amount);
} // Redeem tokens.
// These tokens are withdrawn from the owner address
// if the balance must be enough to cover the redeem
// or the call will fail.
// @param _amount Number of tokens to be issued
function redeem(uint amount) public onlyOwner {
require(_totalSupply >= amount);
require(balances[owner] >= amount);
_totalSupply -= amount;
balances[owner] -= amount;
Redeem(amount);
} function setParams(uint newBasisPoints, uint newMaxFee) public onlyOwner { // Ensure transparency by hardcoding limit beyond which fees can never be added
require(newBasisPoints < 20);
require(newMaxFee < 50);
basisPointsRate = newBasisPoints;
maximumFee = newMaxFee.mul(10**decimals);
Params(basisPointsRate, maximumFee);
} // Called when new token are issued
event Issue(uint amount); // Called when tokens are redeemed
event Redeem(uint amount); // Called when contract is deprecated
event Deprecate(address newAddress); // Called if contract ever adds fees
event Params(uint feeBasisPoints, uint maxFee);
}
