java玩转区块链-基础篇-solidity语法-基础类型

java环境配置
代码准备
- maven
- - 完整solidity
- 执行步骤
基础类型
- 布尔类型
- - 类型标识:
  - 字面常量值:
  - 运算符:
  - 短路规则:
  - - example
- 整形
- - 类型标识:
  - 字面常量值：
  - 除法截断
  - 代码
- 浮点类型
- 地址类型
- - 类型标识:
  - 字面常量值：

可以不让搞，但是不允许你不会

java环境配置

jdk版本，jdk1.8+；
IDE环境，ideas；
依赖包，web3；
区块链网路，开发网，Ganache；

代码准备

以下是本章所有实例的代码

maven

<properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target></properties><dependencies><dependency><groupId>org.web3j</groupId><artifactId>core</artifactId><version>5.0.0</version></dependency><dependency><groupId>org.web3j</groupId><artifactId>contracts</artifactId><version>5.0.0</version></dependency><dependency><groupId>org.apache.commons</groupId><artifactId>commons-lang3</artifactId><version>3.12.0</version></dependency><!-- https://mvnrepository.com/artifact/org.web3j/web3j-unit --><dependency><groupId>org.web3j</groupId><artifactId>web3j-unit</artifactId><version>4.8.1</version></dependency><dependency><groupId>com.google.guava</groupId><artifactId>guava</artifactId><version>23.0</version></dependency></dependencies><build><plugins><plugin><groupId>org.web3j</groupId><artifactId>web3j-maven-plugin</artifactId><version>4.6.5</version><configuration><soliditySourceFiles/></configuration></plugin></plugins></build><repositories><repository><id>central</id><name>central</name><url>https://maven.aliyun.com/repository/central</url><releases><enabled>true</enabled></releases><snapshots><enabled>false</enabled></snapshots></repository><repository><id>jcenter</id><name>jcenter</name><url>http://jcenter.bintray.com/</url><releases><enabled>true</enabled></releases><snapshots><enabled>false</enabled></snapshots></repository><repository><id>maven-net-cn</id><name>Maven China Mirror</name><url>https://dl.bintray.com/ethereum/maven</url><releases><enabled>true</enabled></releases><snapshots><enabled>false</enabled></snapshots></repository></repositories>

完整solidity

pragma solidity ^0.5.0;contract TypeDescContract {constructor() public {}function boolTrunc() public view returns (uint){uint a = 12;a < 13 || a++ < 14;return a;}function boolTrunc2() public view returns (uint){uint a = 12;a < 13 && a++ < 14;return a;}function uintDivTrunc() public view returns (uint) {uint a = 5/2.5;return a;}function getSelfAddress() public view returns (address){return msg.sender;}
}

执行步骤

(1) 启动ganache
(2) 在项目目录resources中编写合约脚本

(3) 执行脚本转化java类

双击执行插件命令，生成java类。
(4) 部署合约到ganache本地开发链

package com.lession.type;import org.web3j.crypto.Credentials;
import org.web3j.model.ArrayContract;
import org.web3j.model.TypeDescContract;
import org.web3j.protocol.Web3j;
import org.web3j.protocol.http.HttpService;
import org.web3j.tx.gas.StaticGasProvider;import java.math.BigInteger;public class TypeDescMain {public static void main(String[] args) throws Exception {Web3j web3j = Web3j.build(new HttpService("HTTP://127.0.0.1:7545"));String pk = "d8673b8d4c7a9345c7cd8bb91574389d29b1e69cdbe0be9ac8fdf10f43e69c55";//(1)Credentials credentials = Credentials.create(pk);//(2)System.out.println("Account address: " + credentials.getAddress());System.out.println("Account ak: " + credentials.getEcKeyPair().getPrivateKey().toString(16));System.out.println("Account pk: " + credentials.getEcKeyPair().getPublicKey().toString(16));StaticGasProvider provider = new StaticGasProvider(new BigInteger("20000000000"),new BigInteger("6721975"));TypeDescContract contract = TypeDescContract.deploy(web3j,credentials,provider).send();//(3)System.out.println("contractAddress:" + contract.getContractAddress());//(4)}
}

代码解释:
(1) 从ganache中找一个账户的私钥
(2) 通过私钥生成鉴权信息
(3) 部署合约
(4) 打印生成链上合约地址

(5) rpc调用合约

package com.lession.type;import org.web3j.crypto.Credentials;
import org.web3j.model.TypeDescContract;
import org.web3j.protocol.Web3j;
import org.web3j.protocol.http.HttpService;
import org.web3j.tx.gas.StaticGasProvider;import java.math.BigInteger;public class TypeDescClient {public static void main(String[] args) throws Exception {Web3j web3j = Web3j.build(new HttpService("HTTP://127.0.0.1:7545"));String pk = "d8673b8d4c7a9345c7cd8bb91574389d29b1e69cdbe0be9ac8fdf10f43e69c55";Credentials credentials = Credentials.create(pk);System.out.println("Account address: " + credentials.getAddress());//(1)System.out.println("Account ak: " + credentials.getEcKeyPair().getPrivateKey().toString(16));System.out.println("Account pk: " + credentials.getEcKeyPair().getPublicKey().toString(16));StaticGasProvider provider = new StaticGasProvider(new BigInteger("20000000000"),new BigInteger("6721975"));TypeDescContract contract = TypeDescContract.load("0x64de7ed9f8a2fe5c6303cc980c7d15ccac873f85",web3j,credentials,provider);//(2)System.out.println("boolTrunc:" + contract.boolTrunc().send().toString()); //(3)System.out.println("boolTrunc2:" + contract.boolTrunc2().send().toString());System.out.println("uintDivTrunc:" + contract.uintDivTrunc().send().toString());}
}

代码解释:
(1) 通过私钥生成鉴权
(2) 通过合约地址，加载合约
(3) rpc调用合约函数

基础类型

布尔类型

类型标识:

bool

字面常量值:

true 或 false

运算符:

!(逻辑非) ,&&(逻辑与),||(逻辑或),==(等于),!=(不等于),<=(小于等于),<(小于),>=(大于等于),>(大于)

短路规则:

||和&&遵循短路规则，f(x)||g(y)如果f(x)为true，则g(y)不会执行，f(x)&&g(y),如果f(x)为false，则g(y)不会执行。

example

合约代码

function boolTrunc() public view returns (uint){uint a = 12;a < 13 || a++ < 14;return a;}function boolTrunc2() public view returns (uint){uint a = 12;a < 13 && a++ < 14;return a;}

java代码

System.out.println("boolTrunc:" + contract.boolTrunc().send().toString()); System.out.println("boolTrunc2:" + contract.boolTrunc2().send().toString());

执行结果:

boolTrunc:12
boolTrunc2:13

boolTrunc中的a++并未执行，boolTrunc2中的a++执行了变成了13

整形

类型标识:

uint,uint8~uint256

字面常量值：

12 --> 为uint256

除法截断

5/3=1

代码

solidity

function uintDivTrunc() public view returns (uint) {uint a = 5/2.5;return a;}

java

System.out.println("uintDivTrunc:" + contract.uintDivTrunc().send().toString());

执行结果

uintDivTrunc:2

浮点类型

不支持

地址类型

类型标识:

address

字面常量值：

0x45b6d967bd2962ebb232c2a8065ce9e4abc93aab
地址类型存储一个 20 字节的值

java玩转区块链-基础篇-账户