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Web3.js查询以太币和代币余额及转账

作者：JackieDYH

这篇文章主要介绍了Web3.js查询以太币和代币余额以及转账,本文通过实例代码给大家介绍的非常详细，对大家的学习或工作具有一定的参考借鉴价值，需要的朋友可以参考下

安装

npm install web3

web3.js查询以太币及代币余额以及进行以太币和代币转账

在私链和主链上查询以太币及代币余额

查询类方法在私链和主链上的方法都是一样的

主链地址。可以去infura申请

contractAbi。合约的abi。可以去https://etherscan.io获取，如果代币合约提供了code，就会有abi

// 引入web3
var Web3 = require('web3');
if (typeof web3 !== 'undefined') {
    web3 = new Web3(web3.currentProvider);
} else {
    // web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:7545"));
    web3 = new Web3(new Web3.providers.HttpProvider("https://mainnet.infura.io/yourAddress"));
}
 
// 定义合约abi
var contractAbi = [{"constant":true,"inputs":[],"name":"mintingFinished","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_value","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_from","type":"address"},{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"cap","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[],"name":"unpause","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_amount","type":"uint256"}],"name":"mint","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_value","type":"uint256"}],"name":"burn","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"paused","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_subtractedValue","type":"uint256"}],"name":"decreaseApproval","outputs":[{"name":"success","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"}],"name":"balanceOf","outputs":[{"name":"balance","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[],"name":"finishMinting","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"pause","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"owner","outputs":[{"name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_addedValue","type":"uint256"}],"name":"increaseApproval","outputs":[{"name":"success","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"},{"name":"_spender","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"newOwner","type":"address"}],"name":"transferOwnership","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"inputs":[],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"name":"burner","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Burn","type":"event"},{"anonymous":false,"inputs":[],"name":"Pause","type":"event"},{"anonymous":false,"inputs":[],"name":"Unpause","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"to","type":"address"},{"indexed":false,"name":"amount","type":"uint256"}],"name":"Mint","type":"event"},{"anonymous":false,"inputs":[],"name":"MintFinished","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"owner","type":"address"},{"indexed":true,"name":"spender","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"from","type":"address"},{"indexed":true,"name":"to","type":"address"},{"indexed":false,"name":"value","type":"uint256"}],"name":"Transfer","type":"event"}];
 
// 合约地址
var contractAddress = "0x7FCCF800568747b178c6cBbe4Bf3d147df75ac61";
 
// 账号
var currentAccount = "0x4e9d5c58d8d6f02FFe5A6EF10CB804FfFB556bBb";
 
// 定义合约
var myContract = new web3.eth.Contract(contractAbi, contractAddress, {
    from: currentAccount, // default from address
    gasPrice: '10000000000' // default gas price in wei, 10 gwei in this case
});
 
// 查询以太币余额
web3.eth.getBalance(currentAccount).then(console.log);
 
// 查看某个账号的代币余额
myContract.methods.balanceOf(contractAddress).call({from: currentAccount}, function(error, result){
    if(!error) {
        console.log(result);
    } else {
        console.log(error);
    }
});

这里还可以查询代币的名称，符号，小数位，发行总量等等，因为代币合约一般都符合ERC标准，都有这些基本方法。甚至如果你有合约代码和abi，还可以调用合约的其他方法，当然调用有些方法需要权限及前置条件

// 获得代币名称
myContract.methods.name().call({from: currentAccount}, function(error, result){
    if(!error) {
          console.log(result);
    } else {
      console.log(error);
    }
});
 
// 获取代币符号
myContract.methods.symbol().call({from: currentAccount}, function(error, result){
    if(!error) {
      console.log(result);
     } else {
      console.log(error);
     }
});
 
// 获取代币总量
myContract.methods.totalSupply().call({from: currentAccount}, function(error, result){
    if(!error) {
      console.log(result);
     } else {
      console.log(error);
     }
});
 
// 查看某个账号允许另一个账号可使用的代币数量
myContract.methods.allowance(sender, spender).call({from: currentAccount}, function(error, result){
    if(!error) {
      console.log(result);
     } else {
      console.log(error);
     }
});

在私链上转账以太币及代币

// 以太币转账
web3.eth.sendTransaction({
    from: currentAccount,
    to: receiverAccount,
    value: '1000000000000000'
})
.then(function(receipt){
    console.log(receipt);
});
 
// 代币转账
myContract.methods.transfer(to, amount).send({from: currentAccount}), function(error, transactionHash){
    if(!error) {
       console.log('transactionHash is ' + transactionHash);
    } else {
       console.log(error);
    }
});

在主链上转账以太币及代币

上面的方法只适用于私链。因为你在私链的账户在本地是有私钥的。而在主链上要进行写入数据的方法，是需要获取账户的私钥并对交易进行签名的，所以要用到web3.eth.sendSignedTransaction方法-文档

npm install ethereumjs-tx

以太币转账

// 引入ethereumjs-tx
var Tx = require('ethereumjs-tx');
 
// 以太币转账    
// 先获取当前账号交易的nonce
web3.eth.getTransactionCount(currentAccount, web3.eth.defaultBlock.pending).then(function(nonce){
 
    
    // 获取交易数据
    var txData = {
        // nonce每次++，以免覆盖之前pending中的交易
        nonce: web3.utils.toHex(nonce++),
        // 设置gasLimit和gasPrice
        gasLimit: web3.utils.toHex(99000),   
        gasPrice: web3.utils.toHex(10e9),  
        // 要转账的哪个账号  
        to: '0x3b11f5CAB8362807273e1680890A802c5F1B15a8',
        // 从哪个账号转
        from: currentAccount,
        // 0.001 以太币
        value: web3.utils.toHex(10e14),         
        data: ''
    }
 
    var tx = new Tx(txData);
 
    // 引入私钥，并转换为16进制
    const privateKey = new Buffer('your account privateKey', 'hex'); 
 
    // 用私钥签署交易
    tx.sign(privateKey);
 
    // 序列化
    var serializedTx = tx.serialize().toString('hex');
 
    web3.eth.sendSignedTransaction('0x' + serializedTx.toString('hex'), function(err, hash) {
        if (!err) {
            console.log(hash);
        } else {
            console.error(err);
        }
    });
});

代币转账

// 补齐64位，不够前面用0补齐
function addPreZero(num){
  var t = (num+'').length,
  s = '';
  for(var i=0; i<64-t; i++){
    s += '0';
  }
  return s+num;
}
 
web3.eth.getTransactionCount(currentAccount, web3.eth.defaultBlock.pending).then(function(nonce){
 
    // 获取交易数据
    var txData = {
        nonce: web3.utils.toHex(nonce++),
        gasLimit: web3.utils.toHex(99000),   
        gasPrice: web3.utils.toHex(10e9),
        // 注意这里是代币合约地址    
        to: contractAddress,
        from: currentAccount,
        // 调用合约转账value这里留空
        value: '0x00',         
        // data的组成，由：0x + 要调用的合约方法的function signature + 要传递的方法参数，每个参数都为64位(对transfer来说，第一个是接收人的地址去掉0x，第二个是代币数量的16进制表示，去掉前面0x，然后补齐为64位)
        data: '0x' + 'a9059cbb' + addPreZero('3b11f5CAB8362807273e1680890A802c5F1B15a8') + addPreZero(web3.utils.toHex(1000000000000000000).substr(2))
    }
 
    var tx = new Tx(txData);
 
    const privateKey = new Buffer('your account privateKey', 'hex'); 
 
    tx.sign(privateKey);
 
    var serializedTx = tx.serialize().toString('hex');
 
    web3.eth.sendSignedTransaction('0x' + serializedTx.toString('hex'), function(err, hash) {
        if (!err) {
            console.log(hash);
        } else {
            console.error(err);
        }
    });
});

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