安利C#开发以太坊区块链的教程：http://t.cn/ReYjplC，又快速学起来的可以看看，php、python、java、js这个网站上都有。
言归正传：
启动容器来执行geth命令
root@ubu-blockchain2:~# docker run -i blockchain101/ethereum-geth:1.6.5 geth attach http://45.32.252.88:8201 Welcome to the Geth JavaScript console! instance: Geth/01/v1.6.5-stable/linux-amd64/go1.8 coinbase: 0x4c57e7e9c2f728046ddc6e96052056a241bdbd0a at block: 6064 (Wed, 02 Aug 2017 01:13:50 UTC) datadir: /ethcluster/779977/data/01 modules: admin:1.0 eth:1.0 net:1.0 rpc:1.0 web3:1.0
查看我们的账户和余额
eth.getBalance(eth.accounts[0]) 11000000000000000000 eth.getBalance(eth.accounts[1]) 0 eth.accounts[0] "0x4c57e7e9c2f728046ddc6e96052056a241bdbd0a" eth.accounts[1] "0xe82e2f0a5abd8774767b9751659976f9c4f59181"
发起一笔交易
>
eth.sendTransaction({from:eth.accounts[0],to:eth.accounts[1],value:web3.toWei(3,'ether')}) "0x0075da712d26aea17d6647035107f509e13eaf3d113c1577db14d4cc4216caec"
查看交易细节
> eth.getTransaction("0x0075da712d26aea17d6647035107f509e13eaf3d113c1577db14d4cc4216caec") { blockHash: "0x3115703894dc6015c96ef4de3e5615f416498ca1f985902b38cd70e27dab8871", blockNumber: 1250, from: "0x4c57e7e9c2f728046ddc6e96052056a241bdbd0a", gas: 90000, gasPrice: 18000000000, hash: "0x0075da712d26aea17d6647035107f509e13eaf3d113c1577db14d4cc4216caec", input: "0x", nonce: 0, r: "0x2aef2c1fa03a0fa4172d21e3383d8c0431d45ec855b9d16efdd5eb2de90c414c", s: "0xc4d530fb7902bf509fe56bfbea4861bf6cc16791afc9c9103c1a18f77407d1f", to: "0xe82e2f0a5abd8774767b9751659976f9c4f59181", transactionIndex: 0, v: "0x17cdb6", value: 3000000000000000000 } > eth.getBalance(eth.accounts[1]) 3000000000000000000
验证用户0的余额
> eth.getBalance(eth.accounts[0]) 7999622000000000000
编写一个简单的合约
contract Sample { uint public value; function Sample(uint v){ value=v; } function set(uint v){ value=v; } function get() constant returns (uint){ return value; } }
在remix网页编译得到ABI接口和合约的二进制代码、
abi=[{"constant":true,"inputs":[],"name":"value","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},
{"constant":false,"inputs":[{"name":"v","type":"uint256"}],"name":"set","outputs":[],"payable":false,"type":"function"},
{"constant":true,"inputs":[],"name":"get","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},
{"inputs":[{"name":"v","type":"uint256"}],"payable":false,"type":"constructor"}]
[{
constant: true,
inputs: [],
name: "value",
outputs: [{
name: "",
type: "uint256"
}],
payable: false,
type: "function"
}, {
constant: false,
inputs: [{
name: "v",
type: "uint256"
}],
name: "set",
outputs: [],
payable: false,
type: "function"
}, {
constant: true,
inputs: [],
name: "get",
outputs: [{
name: "",
type: "uint256"
}],
payable: false,
type: "function"
}, {
inputs: [{
name: "v",
type: "uint256"
}],
payable: false,
type: "constructor"
}]
需要使用eth.contract来定义一个合约类
> sample=eth.contract(abi) { abi: [{ constant: true, inputs: [], name: "value", outputs: [{...}], payable: false, type: "function" }, { constant: false, inputs: [{...}], name: "set", outputs: [], payable: false, type: "function" }, { constant: true, inputs: [], name: "get", outputs: [{...}], payable: false, type: "function" }, { inputs: [{...}], payable: false, type: "constructor" }], eth: { accounts: ["0x4c57e7e9c2f728046ddc6e96052056a241bdbd0a", "0xe82e2f0a5abd8774767b9751659976f9c4f59181"], blockNumber: 6225, coinbase: "0x4c57e7e9c2f728046ddc6e96052056a241bdbd0a", compile: { lll: function(), serpent: function(), solidity: function() }, defaultAccount: undefined, defaultBlock: "latest", gasPrice: 18000000000, hashrate: 0, mining: false, pendingTransactions: [], protocolVersion: "0x3f", syncing: false, call: function(), contract: function(abi), estimateGas: function(), filter: function(fil, callback), getAccounts: function(callback), getBalance: function(), getBlock: function(), getBlockNumber: function(callback), getBlockTransactionCount: function(), getBlockUncleCount: function(), getCode: function(), getCoinbase: function(callback), getCompilers: function(), getGasPrice: function(callback), getHashrate: function(callback), getMining: function(callback), getPendingTransactions: function(callback), getProtocolVersion: function(callback), getRawTransaction: function(), getRawTransactionFromBlock: function(), getStorageAt: function(), getSyncing: function(callback), getTransaction: function(), getTransactionCount: function(), getTransactionFromBlock: function(), getTransactionReceipt: function(), getUncle: function(), getWork: function(), iban: function(iban), icapNamereg: function(), isSyncing: function(callback), namereg: function(), resend: function(), sendIBANTransaction: function(), sendRawTransaction: function(), sendTransaction: function(), sign: function(), signTransaction: function(), submitTransaction: function(), submitWork: function() }, at: function(address, callback), getData: function(), new: function() }
合约的二进制代码赋值给SampleHEX方便使用
SampleHEX="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"
把合约代码部署上链
> thesample=sample.new(1,{from:eth.accounts[0],data:SampleHEX,gas:3000000}) { abi: [{ constant: true, inputs: [], name: "value", outputs: [{...}], payable: false, type: "function" }, { constant: false, inputs: [{...}], name: "set", outputs: [], payable: false, type: "function" }, { constant: true, inputs: [], name: "get", outputs: [{...}], payable: false, type: "function" }, { inputs: [{...}], payable: false, type: "constructor" }], address: undefined, transactionHash: "0xee74bcb4461c9712ec9aca96a5a3a4c3c64be1213854d519fc8e5432b554f7a1" }
查看交易细节
> samplerecpt=eth.getTransactionReceipt("0xee74bcb4461c9712ec9aca96a5a3a4c3c64be1213854d519fc8e5432b554f7a1") { blockHash: "0xddba16545af882835fb9a69a0e5f3b9287c61664837d5ea0068b38575cb665c5", blockNumber: 6246, contractAddress: "0x7504fa9d64ab290844b82660d43b310f8fba0276", cumulativeGasUsed: 141836, from: "0x4c57e7e9c2f728046ddc6e96052056a241bdbd0a", gasUsed: 141836, logs: [], logsBloom: "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", root: "0xd1093ecaca9cc0d10e82a533a15feccedf7ff5c79fb3ebd9366ec0b35dbef478", to: null, transactionHash: "0xee74bcb4461c9712ec9aca96a5a3a4c3c64be1213854d519fc8e5432b554f7a1", transactionIndex: 0 }
合约命名
> samplecontract=sample.at("0x7504fa9d64ab290844b82660d43b310f8fba0276") { abi: [{ constant: true, inputs: [], name: "value", outputs: [{...}], payable: false, type: "function" }, { constant: false, inputs: [{...}], name: "set", outputs: [], payable: false, type: "function" }, { constant: true, inputs: [], name: "get", outputs: [{...}], payable: false, type: "function" }, { inputs: [{...}], payable: false, type: "constructor" }], address: "0x7504fa9d64ab290844b82660d43b310f8fba0276", transactionHash: null, allEvents: function(), get: function(), set: function(), value: function() }
合约查看功能函数get（）,然后调用set()函数，再get()查看时已经改变了
samplecontract.get.call() 1 > samplecontract.set.sendTransaction(9, {from:eth.accounts[0], gas:3000000}) "0x822ee6fb4caceb7e844c533f7f3bc57806f7cb3676fb3066eb848cca46b2f38a" > samplecontract.get.call() 9
我们再打开一个终端，打开cluster1的peer02的控制台，直接at到上一个终端部署的智能合约地址并进行set操作
root@ubu-blockchain2:~/ethereum-docker/ethereum-docker/ethereum-testnet-docker/dockercomposefiles# docker run -i blockchain101/ethereum-geth:1.6.5 geth attach http://45.32.252.88:9201 Welcome to the Geth JavaScript console! > abi=[{"constant":true,"inputs":[],"name":"value","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"v","type":"uint256"}],"name":"set","outputs":[],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"get","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"inputs":[{"name":"v","type":"uint256"}],"payable":false,"type":"constructor"}] > sample=eth.contract(abi) SampleHEX="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"
直接把合约地址赋值并进行set操作
samplecontract=sample.at("0x7504fa9d64ab290844b82660d43b310f8fba0276") > samplecontract.get.call() 9
简单的方法来了。智能合约的部署需要编译，这里用在线编译：
https://ethereum.github.io/browser-solidity/#version=soljson-v0.4.14+commit.c2215d46.js
修改编译好的abi和对象名称：
这里在网上找了个代币的只能合约，可以进行充值、转账和查询，issue 函数可以向充值以太到合约账户，transfer 函数可以向其他账号发送token，getBalance 函数可以获取某个账号的token余额，代码如下： pragma solidity ^0.4.2; contract Token { address issuer; mapping (address => uint) balances; event Issue(address account, uint amount); event Transfer(address from, address to,uint amount); function Token() { issuer = msg.sender; } function issue(address account, uintamount) { if (msg.sender != issuer) throw; balances[account] += amount; } function transfer(address to, uint amount){ if (balances[msg.sender] < amount)throw; balances[msg.sender] -= amount; balances[to] += amount; Transfer(msg.sender, to, amount); } function getBalance(address account)constant returns (uint) { return balances[account]; } } 修改编译好的gas和对象名称： varbrowser_untitled_sol_tokenContract =web3.eth.contract([{"constant":false,"inputs":[{"name":"account","type":"address"},{"name":"amount","type":"uint256"}],"name":"issue","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"to","type":"address"},{"name":"amount","type":"uint256"}],"name":"transfer","outputs":[],"payable":false,"type":"function"},{"constant":true,"inputs":[{"name":"account","type":"address"}],"name":"getBalance","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"inputs":[],"payable":false,"type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"name":"account","type":"address"},{"indexed":false,"name":"amount","type":"uint256"}],"name":"Issue","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"from","type":"address"},{"indexed":false,"name":"to","type":"address"},{"indexed":false,"name":"amount","type":"uint256"}],"name":"Transfer","type":"event"}]); var token =browser_untitled_sol_tokenContract.new( { from: web3.eth.accounts[0], data:'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', gas: '4300000' }, function (e, contract){ console.log(e, contract); if (typeof contract.address !=='undefined') { console.log('Contract mined! address:' + contract.address + ' transactionHash: ' + contract.transactionHash); } })
此时输入合约部署的实例a_demotypes, 可以看到a_demotypes的详情。
控制台调用
> a_demotypes { abi: [{ constant: false, inputs: [{...}], name: "f", outputs: [{...}], payable: false, type: "function" }], address: "0x54ed7a5f5a63ddada3bfe83b3e632adabaa5fc2f", transactionHash: "0x69cde62bcd6458e14f40497f4840f422911d63f5dea2b3a9833e6810db64a1c9", allEvents: function(), f: function() }
这里重点就是address表示的是合约的地址，你会发现这个和账号的信息结果一样，其实你也可以把这个合约地址看做是一个账号地址，后面我们外部调用到的就是这个合约地址。
充值 token.issue.sendTransaction(eth.accounts[0],100, {from: eth.accounts[0]}); 发送 token token.transfer(eth.accounts[1], 30, {from:eth.accounts[0]}) 查看余额 token.getBalance() 控制台调用就不多说，和Java对象调用一样，直接调用即可
外部接口与智能合约交互
以太坊对外提供的有很多接口JSON RPC接口，web3接口，这里我们用JSON RPC接口。
相关API: https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_sendrawtransaction
合约交互的原理
合约的交互都是一次交易，而我们要做的就是把要调用的方法和参数按照api规定的以参数的形式向区块请求一次交易，ethereum接收到我们的请求后通过解析传递的参数来执行相关的合约代码。
RPC接口给我们提供了俩个方法：eth_sendTransaction和eth_call。
eth_sendTransaction Createsnew message call transaction or a contract creation, if the data field containscode. Parameters Object - The transaction object from: DATA, 20 Bytes - The address the transaction is send from. to: DATA, 20 Bytes - (optional when creating new contract) The address the transaction is directed to. gas: QUANTITY - (optional, default: 90000) Integer of the gas provided for the transaction execution. It will return unused gas. gasPrice: QUANTITY - (optional, default: To-Be-Determined) Integer of the gasPrice used for each paid gas value: QUANTITY - (optional) Integer of the value send with this transaction data: DATA - The compiled code of a contract OR the hash of the invoked method signature and encoded parameters. For details see Ethereum Contract ABI nonce: QUANTITY - (optional) Integer of a nonce. This allows to overwrite your own pending transactions that use the same nonce.
可以看到，如果我们创建的为合约时，我们只需要from,to(文档上写的是可选的，但是实际操作中没有to为null的话合约不能正常执行，建议还是加上，这个值就是前面我们部署合约后生成的合约address),data。Data的属性的值具体可以看Contract ABI。这里大概说下：
Data的值相对来说不是固定的，具体怎么生成与合约的参数类型，参数数量都有关联。这里我们以部署的token合约的三个方法为例：
充值issue (address account, uint amount)
这个方法有俩个参数，address充值账号，uint充值数量。
根据Contract ABI，data值应该为方法名的sha3的前8个字节+参数的64字节，不够前面补充为0。
这里方法名并不是issue (address account, uint amount)而是issue(address,uint256)的sha3值。
web3.sha3("issue(address,uint256)")
"0x867904b44b606800f6f10498e11292d04ea19bfc7fe4bc0f1695aa516381f73d"
我们往第一个账号充值10，这里的数据不是以太币，而是我们自己创建的代币。
eth.accounts[0]
"0x0cc9684af605bae10de801218321c1336bb62946"
将10转换为16进制为
000000000000000000000000000000000000000000000000000000000000000a
那么data的数据为：
0x867904b4000000000000000000000000fdf57e81872562a6112656f961944ce821fdf7eb000000000000000000000000000000000000000000000000000000000000000a
那么最后我们调用eth_sendTransaction方法传递参数JSON对象为：
{ from:0xfdf57e81872562a6112656f961944ce821fdf7eb, to:0x7fe133950fc010ce41322d88f64f1918b9abb3a3, data: 0x867904b4000000000000000000000000fdf57e81872562a6112656f961944ce821fdf7eb000000000000000000000000000000000000000000000000000000000000000a }
返回：此交易的hash值,此时该交易还没有执行，只是创建，还需要矿工通过挖矿才能完成。
调用接口方法：
JsonRpcHttpClient client = newJsonRpcHttpClient(new URL(“http://127.0.0.1:8545”)); Object result = client.invoke(methodName,params, Object.class);
通过控制台查看第一个账号已有代币：
token.getbalance(eth.accounts[0])
执行调用接口代码。返回交易hash值：
此时控制台输入：
交易和充值一样，需要注意的是代币转出账号为from属性的值，代币转入账号为data属性里的值，to对应的是合约地址。
eth_call
Executes anew message call immediately without creating a transaction on the block chain. Parameters Object - The transaction call object from: DATA, 20 Bytes - (optional) The address the transaction is sent from. to: DATA, 20 Bytes - The address the transaction is directed to. gas: QUANTITY - (optional) Integer of the gas provided for the transaction execution. eth_call consumes zero gas, but this parameter may be needed by some executions. gasPrice: QUANTITY - (optional) Integer of the gasPrice used for each paid gas value: QUANTITY - (optional) Integer of the value send with this transaction data: DATA - (optional) Hash of the method signature and encoded parameters. For details seeEthereum Contract ABI QUANTITY|TAG - integer block number, or the string "latest", "earliest" or "pending", see the default block parameter
这个方法返回一条信息给我们，相当于数据库的查询功能，参数也是三个，from,to,data，数据格式都是一样的。
查询getBalance(address account)
查询方法hash码：
web3.sha3("getBalance(address)")
"0xf8b2cb4f3943230388faeee074f1503714bff212640051caba01411868d14ae3"
查询我们上一步充值的账号，那么传递的参数data为：
0xf8b2cb4f000000000000000000000000fdf57e81872562a6112656f961944ce821fdf7eb
eth_call方法最后参数为：
{ from: 0xfdf57e81872562a6112656f961944ce821fdf7eb, to:0x7fe133950fc010ce41322d88f64f1918b9abb3a3, data:0xf8b2cb4f000000000000000000000000fdf57e81872562a6112656f961944ce821fdf7eb }
注意，这个方法需要俩参数，处理一个JSONobject外，还有一个字符串参数，这俩可以为“”或者”latest”, “earliest” or “pending”
调用接口返回一个16进制字符串：
0x0000000000000000000000000000000000000000000000000000000000000071就是该账号的代币数量，转换为十进制为：113，与控制查询一致。
这就是一个智能合约的交互过程。是不是很简单啊。
安利两个以太坊相关的实战教程：
区块链初学者 ： 以太坊 DApp 实战开发入门
区块链开发进阶：去中心化以太坊 DApp 电商平台实战开发