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Web3js的使用说明 web3安装与添加

安装npm管理工具
引入web3到工程

npm init npm install web3@0.20.1 # 安装0.20.1版本的web3

创建web3实例

var Web3 = require("web3") var web3 = new Web3(new Web3.providers.HttpProvider("http://192.168.1.114:8989"))

启动geth的私链节点

geth --datadir data1 --networkid 123 --rpc --rpcaddr 192.168.1.114 --rpcport 8989 --port 3000 --dev console

查看node中是否成功连接到对应的私链节点

结果为true表示连接成功

> web3.isConnected() true

大数处理
由于在js中不能正确的处理BigNumber，所以需要引入web3.js依赖的大数处理的库。

//在js中若输入大数，则会表示为科学计数法的形式，忽略掉后面的位数。造成错误 > 101010100324325345346456456456456456456 1.0101010032432535e+38//引入大数处理的库 > var BigNumber = require("bignumber.js/") > var balance = new BigNumber("131242344353464564564574574567456") > balance //s符号位 1=>正数，-1=>负数；e：科学计数法的指数的位数；c：具体的数字 BigNumber { s: 1, e: 32, c: [ 13124, 23443534645645, 64574574567456 ] }

但是20位以上的浮点数会出错，推荐使用wei作为单位，再向用户展示的时候再将wei转换为其他单位可以避免此类错误

//使用超过20位的小数，会忽略后面的值 > var balance = new BigNumber('13124.234435346456466666457455567456'); > balance BigNumber { s: 1, e: 4, c: [ 13124, 23443534645646, 66664574555674, 56000000000000 ] } > balance.toString(10) '13124.23443534645646666646'

基本信息查询

查看web3版本

> web3.version.api '0.20.1'

查看web3连接的节点版本

//同步查询 > web3.version.node 'Geth/v1.8.17-stable/linux-amd64/go1.9.7' //异步查询 > web3.version.getNode(function(err,res) {console.log(res)}) undefined > Geth/v1.8.17-stable/linux-amd64/go1.9.7

网络状态查询

//查看节点连接情况 > web3.isConnected() true //查看当前连接的peer节点 > web3.net.peerCount 0

获取network id

> web3.version.network '123'

provider

//查看当前设置的provider > web3.currentProvider HttpProvider { host: 'http://192.168.1.114:8989', timeout: 0, user: undefined, password: undefined }//修改provider > web3.setProvider(new Web3.providers.HttpProvider("http://localhost:8545")) undefined > web3.currentProvider HttpProvider { host: 'http://localhost:8545', timeout: 0, user: undefined, password: undefined }

web3通用工具方法

以太单位转换

//将wei转换为其他单位 > web3.fromWei("12371221","ether") '0.000000000012371221' //将其他单位转换成wei > web3.toWei("23","ether") '23000000000000000000'

数据类型转换

//16进制转为10进制，参数类型String > web3.toDecimal("0x68") 104//数字转为16进制，参数类型String/Number > web3.fromDecimal(233) '0xe9'//将任意类型转换为16进制 //Number => Hex > web3.toHex(233) '0xe9' //BigNumber => Hex > var bignumber = new BigNumber('12345678901234567890'); undefined > bignumber BigNumber { s: 1, e: 19, c: [ 123456, 78901234567890 ] } > web3.toHex(bignumber) '0xab54a98ceb1f0ad2'//将数字或16进制字符串转换为BigNumber > web3.toBigNumber('12718838912120101') BigNumber { s: 1, e: 16, c: [ 127, 18838912120101 ] }

账户相关操作 web3.eth

查看挖矿成功奖励的地址

> web3.eth.coinbase '0x613d104e6d80ce5a06e7987d39bbd4ee0ccd7656'

账户查询

> web3.eth.accounts [ '0x613d104e6d80ce5a06e7987d39bbd4ee0ccd7656', '0x9f0316428ea5231b7116840df16ae0a768078ffd', '0xf0a545c9bd6dbb358990b9bded9086d4bcbccbc3' ]

区块相关操作 web3.eth

区块高度查询

> web3.eth.blockNumber 10

查询对应块号或哈希值锁对应的区块信息

//同步 > web3.eth.getBlock(9) { difficulty: BigNumber { s: 1, e: 0, c: [ 2 ] }, extraData: '0xd783010811846765746887676f312e392e37856c696e757800000000000000004a14e4a438d226bdb21674de94d54628d4e7b2018cc8aa72f353c22aa57721152e558c24e5b365e484fbc3cc3e66025fcbdf4464954c9055476e2ab40c383f1500', gasLimit: 6338608, gasUsed: 97782, hash: '0x7aa8a046b41db5caaf64ab527dcfdd283deb41e9a9ef7901b07ea8def687a9fe', logsBloom: '0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000', miner: '0x0000000000000000000000000000000000000000', mixHash: '0x0000000000000000000000000000000000000000000000000000000000000000', nonce: '0x0000000000000000', number: 9, parentHash: '0x0c7a2356c3b6b6ee1433046486bfb5f63a2f19208f9549889907fd12a1f34ba4', receiptsRoot: '0x50ff7c4ac1e71c5c0f0c8e5e006872ff4e4a3ca9fc752ee220414fb023d5c890', sha3Uncles: '0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347', size: 890, stateRoot: '0x25b55bbcaf1b57c88c106525cbc47964b0bdf3d2916d794e870169dbd0b4befd', timestamp: 1590246978, totalDifficulty: BigNumber { s: 1, e: 1, c: [ 19 ] }, transactions: [ '0xbdf2740b6a1ed58ec937f6d14a40befbd736df55bc247d25d16d6ee82bae7db5' ], transactionsRoot: '0x407fd28af2c8c3208986b86b9f1a68229d7d8806be489c986ceb9036dc244030', uncles: [] } //异步 > web3.eth.getBlock(9,function(err,res){console.log(res)})

查询相应区块号或哈希值的区块中交易的数量

> web3.eth.getBlockTransactionCount(9) 1

交易相关操作

查询余额

//查询第1个账户的余额 // > web3.eth.getBalance('0x9f0316428ea5231b7116840df16ae0a768078ffd') 账户的哈希 > web3.eth.getBalance(web3.eth.accounts[1]) BigNumber { s: 1, e: 18, c: [ 49999, 99999999447756 ] }

交易查询

>web3.eth.getTransaction('0xbdf2740b6a1ed58ec937f6d14a40befbd736df55bc247d25d16d6ee82bae7db5') { blockHash: '0x7aa8a046b41db5caaf64ab527dcfdd283deb41e9a9ef7901b07ea8def687a9fe', blockNumber: 9, from: '0x613d104e6d80ce5a06e7987d39bbd4ee0ccd7656', gas: 2000000, gasPrice: BigNumber { s: 1, e: 0, c: [ 1 ] }, hash: '0xbdf2740b6a1ed58ec937f6d14a40befbd736df55bc247d25d16d6ee82bae7db5', input: '0x60606040523415600e57600080fd5b60a98061001c6000396000f30060606040526000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff168063f70d290d14603c57600080fd5b3415604657600080fd5b605a60048080359060200190919050506070565b6040518082815260200191505060405180910390f35b60006006820290509190505600a165627a7a723058209c556cf72bbb74d10d06054e5c38c2aaaa68a04f4f4014106c120d4d0c01fa450029', nonce: 3, to: null, transactionIndex: 0, value: BigNumber { s: 1, e: 0, c: [ 0 ] }, v: '0xa95', r: '0x272a84024a654551dd91c0de9e403f13c845d575e974a73d6a00ff42267e3205', s: '0x7bbad81d6b1c531d15bffe4e6fbfa7dd82402d83c5224eb4e40733802a494b9a' }

gas消耗量估计

//仅转账则消耗21000，加入data后会有所增加 >web3.eth.estimateGas({from:web3.eth.accounts[0],to:web3.eth.accounts[1],value:200000,data:"0x1781723939abcdef"}) 21544

发送交易

//发送交易前 > web3.eth.getBalance(web3.eth.accounts[1]) BigNumber { s: 1, e: 18, c: [ 50000, 886987 ] } //向1号账户发送交易，在发送交易前需要先解锁0号账户 //在geth中使用如下命令解锁0号账户 //personal.unlockAccount(personal.listAccounts[0]) >web3.eth.sendTransaction({from:web3.eth.accounts[0],to:web3.eth.accounts[1],value:100000,data:"0x6879ab"}) '0x0247659c53a6df654d033346ee32276d42459d37eb774d5564d03b3dbb086ce9' //发送交易后(需挖矿上链) > web3.eth.getBalance(web3.eth.accounts[1]) BigNumber { s: 1, e: 18, c: [ 50000, 986987 ] }

创建合约相关操作

法一，在本地使用geth的console命令行创建合约

编写solidity程序

//编写solidity程序，保存到HelloWorld.sol文件中 pragma solidity ^0.4.17; contract HelloWorld{ string name = "yorick"; function getName() public view returns(string){ return name; }function setName(string _name) public{ name = _name; }function pureTest(string _name) pure public returns(string){ return _name; } }

使用solcjs编译solidity合约文件，生成bin和abi两个文件

# 使用solcjs编译solidity合约文件，生成bin和abi两个文件 $ solcjs --bin --abi HelloWorld.sol HelloWorld.solHelloWorld_sol_HelloWorld.abiHelloWorld_sol_HelloWorld.bin

geth启动私链

# geth启动私链 geth --datadir data1 --networkid 123 --rpc --rpcaddr 192.168.1.114 --rpcport 8989 --port 3000 --dev console

在geth的console中部署合约

// 定义两个临时存储abi和bin的变量 > var abi = [{"constant":true,"inputs":[],"name":"getName","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"string"}],"name":"setName","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_name","type":"string"}],"name":"pureTest","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"pure","type":"function"}] > var code = "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" // 使用abi创建合约 > var MyContract = eth.contract(abi) // 实例化合约，并部署到区块链中，等待挖矿打包 > var contract = MyContract.new({from:eth.accounts[0],data:code,gas:4700000}) // 部署合约成功可以调用函数查看该合约的地址 > temp.address "0xe1eebf02358f0888aa928d6b0a458783d2a17a11"

法二，通过remix将合约部署到本地(最简单)

在本地开启可以连接remix的私链

# 在本地开启可以连接remix的私链 geth --datadir data1 --networkid 123 --rpc --rpcaddr 192.168.1.114 --rpcport 8989 --port 3000 --dev --rpccorsdomain="http://remix.ethereum.org" --rpcapi web3,eth,debug,personal,net --vmdebug console

打开remix，编写solidity程序并编译

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1.png

编译成功后按如下配置remix的部署环境，其中的私链节点填写在启动geth时候暴露的ip:port，默认为 http://localhost:8545

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点击Deploy部署合约到本地私链

成功后，在remix中可以显示部署的合约交易信息

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3.png 在本地geth的日志中，可以看到挖矿成功，并将合约写入区块的信息

INFO [05-28|22:44:36.185] Setting new local accountaddress=0xE66c8e10ef6FD7888E8c98a0bC5514D66E42a74e INFO [05-28|22:44:36.185] Submitted contract creationfullhash=0x1e32853201463114053d67691832a94407f1ad06f0ec17af73936ab87f0d19ad contract=0x9803466FDC1AE5651F8FaAb4ccD4682231536844 INFO [05-28|22:44:36.185] Commit new mining worknumber=6 sealhash=4d8af1…02b716 uncles=0 txs=0 gas=0 fees=0 elapsed=95.846μs INFO [05-28|22:44:36.186] Sealing paused, waiting for transactions INFO [05-28|22:44:36.186] Commit new mining worknumber=6 sealhash=e3645e…a0c0cb uncles=0 txs=1 gas=345798 fees=3.45798e-13 elapsed=1.074ms INFO [05-28|22:44:36.187] Successfully sealed new blocknumber=6 sealhash=e3645e…a0c0cb hash=72fe7a…0cd95b elapsed=1.289ms INFO [05-28|22:44:36.187]mined potential blocknumber=6 hash=72fe7a…0cd95b INFO [05-28|22:44:36.188] Commit new mining worknumber=7 sealhash=c8812f…e27b0c uncles=0 txs=0 gas=0fees=0elapsed=625.283μs INFO [05-28|22:44:36.188] Sealing paused, waiting for transactions

可以使用remix的图形化接口调用合约中定义的函数

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法三，将remix中编译自动生成的文件放入geth中，一键部署合约

编写好solidity合约程序，并编译。找到编译结果的详细信息，拷贝其中的 WEB3DEPLOY 内容

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将内容直接复制粘贴到本地geth的console中即可，调用address接口可以发现返回地址，说明已成功将合约部署到链上

> var helloworld = helloworldContract.new( ...{ ......from: web3.eth.accounts[0], ......data: '0x60606040526040805190810160405280600681526020017f796f7269636b00000000000000000000000000000000000000000000000000008152506000908051906020019061004f929190610060565b50341561005b57600080fd5b610105565b8280546001816001161561010......data: '0x60606040526040805190810160405280600681526020017f796f7269636b00000000000000000000000000000000000000000000000000008152506000908051906020019061004f929190610060565b50341561005b57600080fd5b610105565b828054600181600116156101000203166002900490600052602060002090601f016020900481019282601f106100a157805160ff19168380011785556100cf565b828001600101855582156100cf579182015b828111156100ce57825......data: '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......data: '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......data: '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......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); .........} ......}) INFO [05-28|22:53:42.506] Setting new local accountaddress=0xE66c8e10ef6FD7888E8c98a0bC5514D66E42a74e INFO [05-28|22:53:42.506] Submitted contract creationfullhash=0xbc723bad1013ffbe484b7751b06789728639f6dcfd65526545e0e10a0398aac3 contract=0x175400570fadfd92bd976bd498EFB76edaa3872b null [object Object] INFO [05-28|22:53:42.508] Commit new mining worknumber=8 sealhash=c1b44f…9d7c59 uncles=0 txs=0 gas=0 fees=0 elapsed=275.665μs INFO [05-28|22:53:42.509] Sealing paused, waiting for transactions undefined > INFO [05-28|22:53:42.511] Commit new mining worknumber=8 sealhash=476d4f…6d4342 uncles=0 txs=1 gas=345798 fees=3.45798e-13 elapsed=2.994ms INFO [05-28|22:53:42.513] Successfully sealed new blocknumber=8 sealhash=476d4f…6d4342 hash=2a11a0…8c2557 elapsed=4.395ms INFO [05-28|22:53:42.513]mined potential blocknumber=8 hash=2a11a0…8c2557 INFO [05-28|22:53:42.514] Commit new mining worknumber=9 sealhash=e2b19c…2832a0 uncles=0 txs=0 gas=0fees=0elapsed=396.974μs INFO [05-28|22:53:42.517] Sealing paused, waiting for transactions null [object Object] Contract mined! address: 0x175400570fadfd92bd976bd498efb76edaa3872b transactionHash: 0xbc723bad1013ffbe484b7751b06789728639f6dcfd65526545e0e10a0398aac3> helloworld.address "0x175400570fadfd92bd976bd498efb76edaa3872b"

【java|web3js基本使用】法五，若合约已经部署到链上，则可以通过abi以及合约地址，得到合约

> var helloworldContract = web3.eth.contract([{"constant":true,"inputs":[],"name":"getName","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"string"}],"name":"setName","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"name":"_name","type":"string"}],"name":"pureTest","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"pure","type":"function"}]); undefined > var contractAddress ="0x175400570fadfd92bd976bd498efb76edaa3872b" undefined > var helloWorld = helloworldContract.at(contractAddress) undefined > helloWorld.address "0x175400570fadfd92bd976bd498efb76edaa3872b" > helloWorld.getName() "yorick"