以太坊开发 HelloWorld for Java
Geth下载
- 官方下载： https://ethereum.github.io/go-ethereum/downloads/
- 国内镜像： https://ethfans.org/wikis/Ethereum-Geth-Mirror
- 其他安装方式： https://github.com/ethereum/go-ethereum/wiki/Building-Ethereum
***** CentOS *****
$ yum -y update
$ yum -y install golang
$ git clone https://github.com/ethereum/go-ethereum
$ cd go-ethereum/
$ make geth
$ ls -al build/bin/geth
如果出错，尝试命令：
$ mv /usr/local/include/iconv.h /usr/local/include/iconv.h.back
初始以太坊
$ geth init genesis.json
自动生成 ~/.ethereum
.
├── geth
│ ├── chaindata
│ │ ├── 000001.log
│ │ ├── CURRENT
│ │ ├── LOCK
│ │ ├── LOG
│ │ └── MANIFEST-000000
│ └── lightchaindata
│ ├── 000001.log
│ ├── CURRENT
│ ├── LOCK
│ ├── LOG
│ └── MANIFEST-000000
├── history
└── keystore
启动以太坊
$ startup.bat # Windows
$ startup.sh # Linux
geth --rpc --rpcaddr "0.0.0.0" --rpcport 8545 --rpccorsdomain "*" --rpcapi "personal,db,eth,net,web3" --networkid 666666 console
--rpc Enable the HTTP-RPC server
--rpcaddr HTTP-RPC server listening interface (default: localhost)
--rpcport HTTP-RPC server listening port (default: 8545)
--rpccorsdomain Comma separated list of domains from which to accept cross origin requests (browser enforced)
--rpcapi API's offered over the HTTP-RPC interface (default: eth,net,web3)
--networkid 区块链ID-私链
--console 命令行模式
钱包
# 查询账户
> eth.accounts
# 创建账户
> personal.newAccount("123456") # 密码123456
# 查询余额
> eth.getBalance(eth.accounts[0])
挖矿
# 开始挖矿 (一个线程挖矿，多线程会很卡)
> miner.start(1)
# 停止挖矿
> miner.stop()
编写合约
- 中文文档 http://www.tryblockchain.org/
- 英文文档 https://solidity.readthedocs.io/
- 在线测试 https://remix.ethereum.org/
部署合约
- 方式一 - remix编译 + geth部署
# 解锁用户
> personal.unlockAccount(eth.account[0])
# 输入代码
> var helloworldContract = web3.eth.contract(......); var helloworld = helloworldContract.new(......)
console: INFO [MM-dd|HH:mm:ss] Submitted contract creation fullhash=0x...... contract=0x......
- 方式二 - web3j ↓
Web3j 轻量级的以太坊开发库 for Java
- Web3j依赖：https://github.com/web3j/web3j/
<dependencies>
<dependency>
<groupId>org.web3j</groupId>
<artifactId>core</artifactId>
<version>4.5.11</version>
</dependency>
</dependencies>
<plugin>
<groupId>org.web3j</groupId>
<artifactId>web3j-maven-plugin</artifactId>
<version>4.5.11</version>
<configuration>
<soliditySourceFiles/>
</configuration>
</plugin>
- 运行插件：Plugins->web3j:generate-sources
resources/HelloWorld.sol ----> org.web3j.model.HelloWorld
- 部署合约：main/java/com/example/demo/HelloWorldDeploy.java
HelloWorld contract = HelloWorld.deploy(web3j, credentials, new DefaultGasProvider()).send();
System.out.println("getContractAddress : " + contract.getContractAddress());
// rewrite: contractAddress ----> application.properties
- 加载合约：main/java/com/example/demo/HelloWorldMain.java
HelloWorld contract = HelloWorld.load(Constants.ADDRESS, web3j, credentials, new DefaultGasProvider());
System.out.println("getContractAddress : " + contract.getContractAddress());
- 项目结构
--com.example.demo.util
----Constants.java 常量
--com.example.demo.test
----ClientVersionTest.java 版本
----TransferEthTest.java 转账
----TransactionGetTest.java Web3j 原生调用合约的 get 方法
----TransactionSetTest.java Web3j 原生调用合约的 set 方法
----FilterTest.java 过滤器
--com.example.demo.contract
----HelloWorldDeploy.java 部署合约
----HelloWorldMain.java 加载合约
Maven镜像
C:\Users\zhang\.m2\settings.xml
<mirrors>
<mirror>
<id>ali-maven</id>
<name>aliyun maven</name>
<url>http://maven.aliyun.com/nexus/content/groups/public/</url>
<mirrorOf>central</mirrorOf>
</mirror>
<mirror>
<id>jboss-maven</id>
<name>jBoss maven</name>
<url>http://repository.jboss.org/nexus/content/groups/public</url>
<mirrorOf>central</mirrorOf>
</mirror>
</mirrors>
错误信息
Usage of API documented as @since 1.8+
解决方法设置如下：
Error:java: Compilation failed: internal java compiler error
解决方法设置如下：
