本文作者:陳進堅
博客地址:https://jian1098.github.io
CSDN博客:https://blog.csdn.net/c_jian
簡書:https://www.jianshu.com/u/8ba9ac5706b6
聯繫方式:[email protected]
環境要求
- 以太坊公鏈或私有鏈
- 一個有以太幣的錢包:用於支付手續費和接收代幣
- EthereumWallet客戶端
部署合約
在Ethereum Wallet客戶端中點擊 CONTRACTS => DEPLOY NEW CONTRACT ,然後FROM填你的以太坊地址,一般會自動填上。在下方SOLIDITY CONTRACT SOURCE CODE的編輯框中填入官方的創建代幣的合約代碼
官方代碼的地址:https://ethereum.org/token ,這個代碼複製到Ethereum Wallet會報"Defining constructors as functions with the same name as the contract is deprecated."的錯誤,把第5行代碼中的合約名字 TokenERC20 改爲 其他名稱即可,例如 Token。
另外如果代幣的小數位數不是18位,需要修改代碼第9行中的 public decimals 爲你需要的小數位數
完整代碼如下
pragma solidity ^0.4.16;
interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external; }
contract Token {
// Public variables of the token
string public name;
string public symbol;
uint8 public decimals = 18;
// 18 decimals is the strongly suggested default, avoid changing it
uint256 public totalSupply;
// This creates an array with all balances
mapping (address => uint256) public balanceOf;
mapping (address => mapping (address => uint256)) public allowance;
// This generates a public event on the blockchain that will notify clients
event Transfer(address indexed from, address indexed to, uint256 value);
// This generates a public event on the blockchain that will notify clients
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
// This notifies clients about the amount burnt
event Burn(address indexed from, uint256 value);
/**
* Constructor function
*
* Initializes contract with initial supply tokens to the creator of the contract
*/
function TokenERC20(
uint256 initialSupply,
string tokenName,
string tokenSymbol
) public {
totalSupply = initialSupply * 10 ** uint256(decimals); // Update total supply with the decimal amount
balanceOf[msg.sender] = totalSupply; // Give the creator all initial tokens
name = tokenName; // Set the name for display purposes
symbol = tokenSymbol; // Set the symbol for display purposes
}
/**
* Internal transfer, only can be called by this contract
*/
function _transfer(address _from, address _to, uint _value) internal {
// Prevent transfer to 0x0 address. Use burn() instead
require(_to != 0x0);
// Check if the sender has enough
require(balanceOf[_from] >= _value);
// Check for overflows
require(balanceOf[_to] + _value >= balanceOf[_to]);
// Save this for an assertion in the future
uint previousBalances = balanceOf[_from] + balanceOf[_to];
// Subtract from the sender
balanceOf[_from] -= _value;
// Add the same to the recipient
balanceOf[_to] += _value;
emit Transfer(_from, _to, _value);
// Asserts are used to use static analysis to find bugs in your code. They should never fail
assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
}
/**
* Transfer tokens
*
* Send `_value` tokens to `_to` from your account
*
* @param _to The address of the recipient
* @param _value the amount to send
*/
function transfer(address _to, uint256 _value) public returns (bool success) {
_transfer(msg.sender, _to, _value);
return true;
}
/**
* Transfer tokens from other address
*
* Send `_value` tokens to `_to` on behalf of `_from`
*
* @param _from The address of the sender
* @param _to The address of the recipient
* @param _value the amount to send
*/
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
require(_value <= allowance[_from][msg.sender]); // Check allowance
allowance[_from][msg.sender] -= _value;
_transfer(_from, _to, _value);
return true;
}
/**
* Set allowance for other address
*
* Allows `_spender` to spend no more than `_value` tokens on your behalf
*
* @param _spender The address authorized to spend
* @param _value the max amount they can spend
*/
function approve(address _spender, uint256 _value) public
returns (bool success) {
allowance[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
/**
* Set allowance for other address and notify
*
* Allows `_spender` to spend no more than `_value` tokens on your behalf, and then ping the contract about it
*
* @param _spender The address authorized to spend
* @param _value the max amount they can spend
* @param _extraData some extra information to send to the approved contract
*/
function approveAndCall(address _spender, uint256 _value, bytes _extraData)
public
returns (bool success) {
tokenRecipient spender = tokenRecipient(_spender);
if (approve(_spender, _value)) {
spender.receiveApproval(msg.sender, _value, this, _extraData);
return true;
}
}
/**
* Destroy tokens
*
* Remove `_value` tokens from the system irreversibly
*
* @param _value the amount of money to burn
*/
function burn(uint256 _value) public returns (bool success) {
require(balanceOf[msg.sender] >= _value); // Check if the sender has enough
balanceOf[msg.sender] -= _value; // Subtract from the sender
totalSupply -= _value; // Updates totalSupply
emit Burn(msg.sender, _value);
return true;
}
/**
* Destroy tokens from other account
*
* Remove `_value` tokens from the system irreversibly on behalf of `_from`.
*
* @param _from the address of the sender
* @param _value the amount of money to burn
*/
function burnFrom(address _from, uint256 _value) public returns (bool success) {
require(balanceOf[_from] >= _value); // Check if the targeted balance is enough
require(_value <= allowance[_from][msg.sender]); // Check allowance
balanceOf[_from] -= _value; // Subtract from the targeted balance
allowance[_from][msg.sender] -= _value; // Subtract from the sender's allowance
totalSupply -= _value; // Update totalSupply
emit Burn(_from, _value);
return true;
}
}
將代碼複製過去之後,發現後邊會出現下拉框,選擇“Token”(就是你合約的名字),然後點擊最下面的“DEPLOY”,在彈出框中輸入賬號密碼等待交易完成。
創建代幣
- 點擊“CONTRACT”會發現在灰色背景的欄目“Custom Contracts”中多了剛剛創建的合約,點擊它進入這個合約。
- 在界面的右下角下拉框選擇“Token ERC 20”,下面的輸入框分別填寫代幣的發行量、具體名稱 (比如Ethereum),代幣符號(就是代幣的單位,比如ETH),然後點擊“EXECUTE”按鈕,輸入賬號密碼等待交易完成。
- 交易完成後點擊“CONTRACT”拉到最下面點擊剛剛創建的代幣,填寫代幣的名稱、符號和位數,點擊OK保存好代幣的信息。
- 首頁點擊你創建代幣的錢包地址,會發現以太幣餘額下面多出一行代幣的餘額。鼠標移上去點擊Send即可發送代幣交易。