这一步在前面文章已经写过
完成后在浏览器打开http://localhost:8080即可在本地IDE编写合约
这一步在前文也有讲过,这里不再赘述。这一步是为最后成功部署连接私有链作准备。
连接私有链
打开http://localhost:8080
编写合约
1.编写合约代码
pragma solidity ^0.4.16;
interface tokenRecipient {
function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) public;
}
contract TokenERC20 {
string public name;
string public symbol;
uint8 public decimals = 18; // 18 是建议的默认值
uint256 public totalSupply;
mapping (address => uint256) public balanceOf; //
mapping (address => mapping (address => uint256)) public allowance;
event Transfer(address indexed from, address indexed to, uint256 value);
event Burn(address indexed from, uint256 value);
function TokenERC20(uint256 initialSupply, string tokenName, string tokenSymbol) public {
totalSupply = initialSupply * 10 ** uint256(decimals);
balanceOf[msg.sender] = totalSupply;
name = tokenName;
symbol = tokenSymbol;
}
function _transfer(address _from, address _to, uint _value) internal {
require(_to != 0x0);
require(balanceOf[_from] >= _value);
require(balanceOf[_to] + _value > balanceOf[_to]);
uint previousBalances = balanceOf[_from] + balanceOf[_to];
balanceOf[_from] -= _value;
balanceOf[_to] += _value;
Transfer(_from, _to, _value);
assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
}
function transfer(address _to, uint256 _value) public returns (bool) {
_transfer(msg.sender, _to, _value);
return true;
}
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;
}
function approve(address _spender, uint256 _value) public
returns (bool success) {
allowance[msg.sender][_spender] = _value;
return true;
}
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;
}
}
function burn(uint256 _value) public returns (bool success) {
require(balanceOf[msg.sender] >= _value);
balanceOf[msg.sender] -= _value;
totalSupply -= _value;
Burn(msg.sender, _value);
return true;
}
function burnFrom(address _from, uint256 _value) public returns (bool success) {
require(balanceOf[_from] >= _value);
require(_value <= allowance[_from][msg.sender]);
balanceOf[_from] -= _value;
allowance[_from][msg.sender] -= _value;
totalSupply -= _value;
Burn(_from, _value);
return true;
}
}
简单说明:
name : 代币名称
symbol: 代币符号
decimals: 代币小数点位数,代币的最小单位, 18表示我们可以拥有 .0000000000000000001单位个代币。
totalSupply() : 发行代币总量。
balanceOf(): 查看对应账号的代币余额。
transfer(): 实现代币交易,用于给用户发送代币(从我们的账户里)。
transferFrom(): 实现代币用户之间的交易。
allowance(): 控制代币的交易,如可交易账号及资产。
approve(): 允许用户可花费的代币数。
2.编译部署
部署成功后
这时候我们切换到账户2向刚刚的步骤一样 添加代币 这时候我们能发现账户1 JHW代币少了10000.账户2多了100000到这里我们转账就正式完成了