14.3. 智能合約入門演示

14.3. 智能合約入門演示
上一頁	第 14 章智能合約語言 Solidity v0.5.0	下一頁

這裡我們先做一個 Helloword 演示，讓你初步對智能合約有一個大概的認識。

	提示
	需要注意的是，你在網上會看到很多例子，對照這例子一步一步操作，始終無法成功，這根Solidity的版本有很大關係。

將下面代碼粘貼到

			
pragma solidity ^0.4.25;

contract HelloWorld
{
    string tmp;

    function HelloWorld() public
    {

    }

    function get() public constant returns (string)
    {
        return tmp;
    }

    function set(string _tmp) public
    {
        tmp = _tmp;
    }

}

Compile - Details - WEB3DEPLOY

			
var helloworldContract = web3.eth.contract([{"constant":false,"inputs":[{"name":"_tmp","type":"string"}],"name":"set","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"get","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"inputs":[],"payable":false,"stateMutability":"nonpayable","type":"constructor"}]);
var helloworld = helloworldContract.new(
   {
     from: web3.eth.accounts[0], 
     data: '0x6060604052341561000f57600080fd5b6102e38061001e6000396000f30060606040526004361061004c576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff1680634ed3885e146100515780636d4ce63c146100ae575b600080fd5b341561005c57600080fd5b6100ac600480803590602001908201803590602001908080601f0160208091040260200160405190810160405280939291908181526020018383808284378201915050505050509190505061013c565b005b34156100b957600080fd5b6100c1610156565b6040518080602001828103825283818151815260200191508051906020019080838360005b838110156101015780820151818401526020810190506100e6565b50505050905090810190601f16801561012e5780820380516001836020036101000a031916815260200191505b509250505060405180910390f35b80600090805190602001906101529291906101fe565b5050565b61015e61027e565b60008054600181600116156101000203166002900480601f0160208091040260200160405190810160405280929190818152602001828054600181600116156101000203166002900480156101f45780601f106101c9576101008083540402835291602001916101f4565b820191906000526020600020905b8154815290600101906020018083116101d757829003601f168201915b5050505050905090565b828054600181600116156101000203166002900490600052602060002090601f016020900481019282601f1061023f57805160ff191683800117855561026d565b8280016001018555821561026d579182015b8281111561026c578251825591602001919060010190610251565b5b50905061027a9190610292565b5090565b602060405190810160405280600081525090565b6102b491905b808211156102b0576000816000905550600101610298565b5090565b905600a165627a7a72305820ea826c30d131f20a4d3a8e3fb059ffa95f4c222a5b099029750e4c1937b46e5b0029', 
     gas: '4700000'
   }, function (e, contract){
    console.log(e, contract);
    if (typeof contract.address !== 'undefined') {
         console.log('Contract mined! address: ' + contract.address + ' transactionHash: ' + contract.transactionHash);
    }
 })

部署智能合約需要消耗 gas 所以你要先解鎖賬號。

			
> personal.unlockAccount("0x83fda0ba7e6cfa8d7319d78fa0e6b753a2bcb5a6", "", 300)
true

			
> var helloworldContract = web3.eth.contract([{"constant":false,"inputs":[{"name":"_tmp","type":"string"}],"name":"set","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"get","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"inputs":[],"payable":false,"stateMutability":"nonpayable","type":"constructor"}]);
undefined
> var helloworld = helloworldContract.new(
...    {
......      from: web3.eth.accounts[0], 
......      data: '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', 
......      gas: '4700000'
......    }, function (e, contract){
......     console.log(e, contract);
......     if (typeof contract.address !== 'undefined') {
.........          console.log('Contract mined! address: ' + contract.address + ' transactionHash: ' + contract.transactionHash);
.........     }
......  })
null [object Object]
undefined

helloworld 智能合約已經創建完畢

			
> helloworld
{
  abi: [{
      constant: false,
      inputs: [{...}],
      name: "set",
      outputs: [],
      payable: false,
      stateMutability: "nonpayable",
      type: "function"
  }, {
      constant: true,
      inputs: [],
      name: "get",
      outputs: [{...}],
      payable: false,
      stateMutability: "view",
      type: "function"
  }, {
      inputs: [],
      payable: false,
      stateMutability: "nonpayable",
      type: "constructor"
  }],
  address: undefined,
  transactionHash: "0x466c9ad9db8f37ed5b65bc261210da92f51364ebab1dcbd3759bfc3e16ad6502"
}

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