區塊鏈技術學習part4 — web3j, a java SDK for Ethereum clients 施工中

tags: tutorials blockchain ethereum smart contract solidity web3j

• 區塊鏈技術學習part4 — web3j, a java SDK for Ethereum clients 施工中
  • 1. web3j簡介
  • 2. 安裝web3j CLI介面
  • 3. 安裝web3j
  • 4. 設定Ganache環境
  • 5. web3j連接Ganache
    • 同步連接
  • 6. solidity編譯
  • web3j 轉換solidity至java
  • web3j via infura in Rinkeby TestNet
    • 前言
    • infura 服務
    • web3j 使用

WU D.FThu, Mar 26, 2020 10:21 AM
↑ Markdown我就爛.jpg
Part3被吃掉惹 等哪天功成名就再補
本篇文章部分截圖為windows環境下 觀念是一樣的小部分差異請自行融會貫通ww

1. web3j簡介

The Web3j SDK provides a seamless experience for development on leading blockchain platforms
看嘸?
web3j是由一個Java撰寫的函式庫，主要是用來提供處理以太坊智慧合約及以太坊網路上的節點，簡單來說它是一個Ethereum Client Library，方便透過該程式庫去與以太坊進行溝通。web3j除了提供原生Java的函式庫也提供可在android上進行使用
還是看嘸

• 官方網站
• github

2. 安裝web3j CLI介面

這個是web3j提供CLI程式庫，這個是方便我們在CLI有一些便捷的指令，其中最重要的是可以在CLI中將我們Smart Contract編譯出來的.abi、.bin檔案轉成Java Class進行對應，這樣當我們操作區塊鏈上的智能合約就能用Java Class對應智能合約進行操作。
JDK Version8+

• unix-like環境：一條指令解決
  • curl -L https://get.web3j.io | bash
• windows版一樣一條 但是長很多
  • 使用PowerShell
    Set-ExecutionPolicy Bypass -Scope Process -Force; iex ((New-Object System.Net.WebClient).Download String('https://raw.githubusercont ent.com/web3j/web3j-installer/master/installer.ps1'))

3. 安裝web3j

• 我使用的是maven 因為我不會Gradle 雖然maven也是看人家的教學弄得…

<dependency>
  <groupId>org.web3j</groupId>
  <artifactId>core</artifactId>
  <version>4.5.12</version>
</dependency>

4. 設定Ganache環境

Ganache的原理就是幫你用好Geth的環境，也就是當你開啟Ganache，它會在你的電腦上開啟一個節點，並且在這個節點初始化多個帳號，因此當測試的時候就可以直接拿這節點的帳號進行測試，尤其對於智能合約的操作是最方便的。

• 官網

• 簡單講就是在local端建立一個私有鏈讓你試爆測試用的工具

  • 有方便的GUI就是讚

• (windows環境限定)下載回來後安裝過程可能會出現警告，到設定介面進行如下設定，覺得自己是開發人員也可以選開發人員模式增加攻擊表面

• 歡迎畫面

• • Account
    • 帳戶，預設給100塊可揮霍
    • 右邊的鑰匙按下去就是private Key了
  • block
    • 以建立的區塊
  • transactions
    • 交易列表
  • contract
    • 部屬上去的合約

5. web3j連接Ganache

同步連接

直接上程式碼：

public class Main {
    public static void main(String[] args) throws Exception {
        // send synchronous requests
        Web3j web3 = Web3j.build(new HttpService("http://127.0.0.1:7545"));
        Web3ClientVersion web3ClientVersion = web3.web3ClientVersion().send();
        String clientVersion = web3ClientVersion.getWeb3ClientVersion();
        System.out.println(clientVersion);
    }
}

• 如果出現:

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

• 請加上：

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-nop</artifactId>
    <version>1.7.25</version>
</dependency>

6. solidity編譯

• 範例程式

pragma solidity ^0.6.2;
contract SimpleStorage {
    uint storedData;
    string storedString;
    
    function set(uint x) public {
        storedData = x;
    }

    function setString(string memory x) public{
        storedString = x;
    }

    function get() public view returns (uint) {
        return storedData;
    }
    
    function getString() public view returns (string memory){
        return storedString;
    }
}

• 在remix中編譯
• 並且在左下角複製byte code和ABI並建立成
  • SimpleStorage.abi
  • SimpleStorage.bin

web3j 轉換solidity至java

web3j solidity generate -b ./SimpleStorage.bin -a ./SimpleStorage.abi -o ./src/main/java -p kenny.home

• b：SimpleStorage.bin的檔案路徑
• a：SimpleStorage.abi的檔案路徑
• o：產生出來對應的Java檔案要放置在哪
• p：你的專案package name

注意 web3j編譯後的檔案請只保留objec的值就好
範例:請將這些

private static final String BINARY = "{\r\n"
            + "\t\"linkReferences\": {},\r\n"
            + "\t\"object\": \"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\",\r\n"
            + "\t\"opcodes\": \"PUSH1 0x80 PUSH1 0x40 MSTORE CALLVALUE DUP1 ISZERO PUSH2 0x10 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH1 0x40 MLOAD PUSH2 0x6C2 CODESIZE SUB DUP1 PUSH2 0x6C2 DUP4 CODECOPY DUP2 ADD DUP1 PUSH1 0x40 MSTORE DUP2 ADD SWAP1 DUP1 DUP1 MLOAD DUP3 ADD SWAP3 SWAP2 SWAP1 POP POP POP CALLER PUSH1 0x0 DUP1 PUSH2 0x100 EXP DUP2 SLOAD DUP2 PUSH20 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF MUL NOT AND SWAP1 DUP4 PUSH20 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF AND MUL OR SWAP1 SSTORE POP DUP1 PUSH1 0x1 SWAP1 DUP1 MLOAD SWAP1 PUSH1 0x20 ADD SWAP1 PUSH2 0x89 SWAP3 SWAP2 SWAP1 PUSH2 0x90 JUMP JUMPDEST POP POP PUSH2 0x135 JUMP JUMPDEST DUP3 DUP1 SLOAD PUSH1 0x1 DUP2 PUSH1 0x1 AND ISZERO PUSH2 0x100 MUL SUB AND PUSH1 0x2 SWAP1 DIV SWAP1 PUSH1 0x0 MSTORE PUSH1 0x20 PUSH1 0x0 KECCAK256 SWAP1 PUSH1 0x1F ADD PUSH1 0x20 SWAP1 DIV DUP2 ADD SWAP3 DUP3 PUSH1 0x1F LT PUSH2 0xD1 JUMPI DUP1 MLOAD PUSH1 0xFF NOT AND DUP4 DUP1 ADD OR DUP6 SSTORE PUSH2 0xFF JUMP JUMPDEST DUP3 DUP1 ADD PUSH1 0x1 ADD DUP6 SSTORE DUP3 ISZERO PUSH2 0xFF JUMPI SWAP2 DUP3 ADD JUMPDEST DUP3 DUP2 GT ISZERO PUSH2 0xFE JUMPI DUP3 MLOAD DUP3 SSTORE SWAP2 PUSH1 0x20 ADD SWAP2 SWAP1 PUSH1 0x1 ADD SWAP1 PUSH2 0xE3 JUMP JUMPDEST JUMPDEST POP SWAP1 POP PUSH2 0x10C SWAP2 SWAP1 PUSH2 0x110 JUMP JUMPDEST POP SWAP1 JUMP JUMPDEST PUSH2 0x132 SWAP2 SWAP1 JUMPDEST DUP1 DUP3 GT ISZERO PUSH2 0x12E JUMPI PUSH1 0x0 DUP2 PUSH1 0x0 SWAP1 SSTORE POP PUSH1 0x1 ADD PUSH2 0x116 JUMP JUMPDEST POP SWAP1 JUMP JUMPDEST SWAP1 JUMP JUMPDEST PUSH2 0x57E DUP1 PUSH2 0x144 PUSH1 0x0 CODECOPY PUSH1 0x0 RETURN STOP PUSH1 0x80 PUSH1 0x40 MSTORE PUSH1 0x4 CALLDATASIZE LT PUSH2 0x57 JUMPI PUSH1 0x0 CALLDATALOAD PUSH29 0x100000000000000000000000000000000000000000000000000000000 SWAP1 DIV PUSH4 0xFFFFFFFF AND DUP1 PUSH4 0x41C0E1B5 EQ PUSH2 0x5C JUMPI DUP1 PUSH4 0x4AC0D66E EQ PUSH2 0x73 JUMPI DUP1 PUSH4 0xCFAE3217 EQ PUSH2 0xDC JUMPI JUMPDEST PUSH1 0x0 DUP1 REVERT JUMPDEST CALLVALUE DUP1 ISZERO PUSH2 0x68 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH2 0x71 PUSH2 0x16C JUMP JUMPDEST STOP JUMPDEST CALLVALUE DUP1 ISZERO PUSH2 0x7F JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH2 0xDA PUSH1 0x4 DUP1 CALLDATASIZE SUB DUP2 ADD SWAP1 DUP1 DUP1 CALLDATALOAD SWAP1 PUSH1 0x20 ADD SWAP1 DUP3 ADD DUP1 CALLDATALOAD SWAP1 PUSH1 0x20 ADD SWAP1 DUP1 DUP1 PUSH1 0x1F ADD PUSH1 0x20 DUP1 SWAP2 DIV MUL PUSH1 0x20 ADD PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 SWAP4 SWAP3 SWAP2 SWAP1 DUP2 DUP2 MSTORE PUSH1 0x20 ADD DUP4 DUP4 DUP1 DUP3 DUP5 CALLDATACOPY DUP3 ADD SWAP2 POP POP POP POP POP POP SWAP2 SWAP3 SWAP2 SWAP3 SWAP1 POP POP POP PUSH2 0x1FD JUMP JUMPDEST STOP JUMPDEST CALLVALUE DUP1 ISZERO PUSH2 0xE8 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH2 0xF1 PUSH2 0x40B JUMP JUMPDEST PUSH1 0x40 MLOAD DUP1 DUP1 PUSH1 0x20 ADD DUP3 DUP2 SUB DUP3 MSTORE DUP4 DUP2 DUP2 MLOAD DUP2 MSTORE PUSH1 0x20 ADD SWAP2 POP DUP1 MLOAD SWAP1 PUSH1 0x20 ADD SWAP1 DUP1 DUP4 DUP4 PUSH1 0x0 JUMPDEST DUP4 DUP2 LT ISZERO PUSH2 0x131 JUMPI DUP1 DUP3 ADD MLOAD DUP2 DUP5 ADD MSTORE PUSH1 0x20 DUP2 ADD SWAP1 POP PUSH2 0x116 JUMP JUMPDEST POP POP POP POP SWAP1 POP SWAP1 DUP2 ADD SWAP1 PUSH1 0x1F AND DUP1 ISZERO PUSH2 0x15E JUMPI DUP1 DUP3 SUB DUP1 MLOAD PUSH1 0x1 DUP4 PUSH1 0x20 SUB PUSH2 0x100 EXP SUB NOT AND DUP2 MSTORE PUSH1 0x20 ADD SWAP2 POP JUMPDEST POP SWAP3 POP POP POP PUSH1 0x40 MLOAD DUP1 SWAP2 SUB SWAP1 RETURN JUMPDEST PUSH1 0x0 DUP1 SWAP1 SLOAD SWAP1 PUSH2 0x100 EXP SWAP1 DIV PUSH20 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF AND PUSH20 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF AND CALLER PUSH20 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF AND EQ ISZERO PUSH2 0x1FB JUMPI PUSH1 0x0 DUP1 SWAP1 SLOAD SWAP1 PUSH2 0x100 EXP SWAP1 DIV PUSH20 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF AND PUSH20 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF AND SELFDESTRUCT JUMPDEST JUMP JUMPDEST DUP1 PUSH1 0x40 MLOAD DUP1 DUP3 DUP1 MLOAD SWAP1 PUSH1 0x20 ADD SWAP1 DUP1 DUP4 DUP4 JUMPDEST PUSH1 0x20 DUP4 LT ISZERO ISZERO PUSH2 0x233 JUMPI DUP1 MLOAD DUP3 MSTORE PUSH1 0x20 DUP3 ADD SWAP2 POP PUSH1 0x20 DUP2 ADD SWAP1 POP PUSH1 0x20 DUP4 SUB SWAP3 POP PUSH2 0x20E JUMP JUMPDEST PUSH1 0x1 DUP4 PUSH1 0x20 SUB PUSH2 0x100 EXP SUB DUP1 NOT DUP3 MLOAD AND DUP2 DUP5 MLOAD AND DUP1 DUP3 OR DUP6 MSTORE POP POP POP POP POP POP SWAP1 POP ADD SWAP2 POP POP PUSH1 0x40 MLOAD DUP1 SWAP2 SUB SWAP1 KECCAK256 PUSH1 0x1 PUSH1 0x40 MLOAD DUP1 DUP3 DUP1 SLOAD PUSH1 0x1 DUP2 PUSH1 0x1 AND ISZERO PUSH2 0x100 MUL SUB AND PUSH1 0x2 SWAP1 DIV DUP1 ISZERO PUSH2 0x2BD JUMPI DUP1 PUSH1 0x1F LT PUSH2 0x29B JUMPI PUSH2 0x100 DUP1 DUP4 SLOAD DIV MUL DUP4 MSTORE SWAP2 DUP3 ADD SWAP2 PUSH2 0x2BD JUMP JUMPDEST DUP3 ADD SWAP2 SWAP1 PUSH1 0x0 MSTORE PUSH1 0x20 PUSH1 0x0 KECCAK256 SWAP1 JUMPDEST DUP2 SLOAD DUP2 MSTORE SWAP1 PUSH1 0x1 ADD SWAP1 PUSH1 0x20 ADD DUP1 DUP4 GT PUSH2 0x2A9 JUMPI JUMPDEST POP POP SWAP2 POP POP PUSH1 0x40 MLOAD DUP1 SWAP2 SUB SWAP1 KECCAK256 PUSH32 0x47DCD1AA8B77B0B943642129C767533EEACD700C7C1EAB092B8CE05D2B2FAF5 PUSH1 0x1 DUP5 PUSH1 0x40 MLOAD DUP1 DUP1 PUSH1 0x20 ADD DUP1 PUSH1 0x20 ADD DUP4 DUP2 SUB DUP4 MSTORE DUP6 DUP2 DUP2 SLOAD PUSH1 0x1 DUP2 PUSH1 0x1 AND ISZERO PUSH2 0x100 MUL SUB AND PUSH1 0x2 SWAP1 DIV DUP2 MSTORE PUSH1 0x20 ADD SWAP2 POP DUP1 SLOAD PUSH1 0x1 DUP2 PUSH1 0x1 AND ISZERO PUSH2 0x100 MUL SUB AND PUSH1 0x2 SWAP1 DIV DUP1 ISZERO PUSH2 0x37B JUMPI DUP1 PUSH1 0x1F LT PUSH2 0x350 JUMPI PUSH2 0x100 DUP1 DUP4 SLOAD DIV MUL DUP4 MSTORE SWAP2 PUSH1 0x20 ADD SWAP2 PUSH2 0x37B JUMP JUMPDEST DUP3 ADD SWAP2 SWAP1 PUSH1 0x0 MSTORE PUSH1 0x20 PUSH1 0x0 KECCAK256 SWAP1 JUMPDEST DUP2 SLOAD DUP2 MSTORE SWAP1 PUSH1 0x1 ADD SWAP1 PUSH1 0x20 ADD DUP1 DUP4 GT PUSH2 0x35E JUMPI DUP3 SWAP1 SUB PUSH1 0x1F AND DUP3 ADD SWAP2 JUMPDEST POP POP DUP4 DUP2 SUB DUP3 MSTORE DUP5 DUP2 DUP2 MLOAD DUP2 MSTORE PUSH1 0x20 ADD SWAP2 POP DUP1 MLOAD SWAP1 PUSH1 0x20 ADD SWAP1 DUP1 DUP4 DUP4 PUSH1 0x0 JUMPDEST DUP4 DUP2 LT ISZERO PUSH2 0x3B5 JUMPI DUP1 DUP3 ADD MLOAD DUP2 DUP5 ADD MSTORE PUSH1 0x20 DUP2 ADD SWAP1 POP PUSH2 0x39A JUMP JUMPDEST POP POP POP POP SWAP1 POP SWAP1 DUP2 ADD SWAP1 PUSH1 0x1F AND DUP1 ISZERO PUSH2 0x3E2 JUMPI DUP1 DUP3 SUB DUP1 MLOAD PUSH1 0x1 DUP4 PUSH1 0x20 SUB PUSH2 0x100 EXP SUB NOT AND DUP2 MSTORE PUSH1 0x20 ADD SWAP2 POP JUMPDEST POP SWAP5 POP POP POP POP POP PUSH1 0x40 MLOAD DUP1 SWAP2 SUB SWAP1 LOG3 DUP1 PUSH1 0x1 SWAP1 DUP1 MLOAD SWAP1 PUSH1 0x20 ADD SWAP1 PUSH2 0x407 SWAP3 SWAP2 SWAP1 PUSH2 0x4AD JUMP JUMPDEST POP POP JUMP JUMPDEST PUSH1 0x60 PUSH1 0x1 DUP1 SLOAD PUSH1 0x1 DUP2 PUSH1 0x1 AND ISZERO PUSH2 0x100 MUL SUB AND PUSH1 0x2 SWAP1 DIV DUP1 PUSH1 0x1F ADD PUSH1 0x20 DUP1 SWAP2 DIV MUL PUSH1 0x20 ADD PUSH1 0x40 MLOAD SWAP1 DUP2 ADD PUSH1 0x40 MSTORE DUP1 SWAP3 SWAP2 SWAP1 DUP2 DUP2 MSTORE PUSH1 0x20 ADD DUP3 DUP1 SLOAD PUSH1 0x1 DUP2 PUSH1 0x1 AND ISZERO PUSH2 0x100 MUL SUB AND PUSH1 0x2 SWAP1 DIV DUP1 ISZERO PUSH2 0x4A3 JUMPI DUP1 PUSH1 0x1F LT PUSH2 0x478 JUMPI PUSH2 0x100 DUP1 DUP4 SLOAD DIV MUL DUP4 MSTORE SWAP2 PUSH1 0x20 ADD SWAP2 PUSH2 0x4A3 JUMP JUMPDEST DUP3 ADD SWAP2 SWAP1 PUSH1 0x0 MSTORE PUSH1 0x20 PUSH1 0x0 KECCAK256 SWAP1 JUMPDEST DUP2 SLOAD DUP2 MSTORE SWAP1 PUSH1 0x1 ADD SWAP1 PUSH1 0x20 ADD DUP1 DUP4 GT PUSH2 0x486 JUMPI DUP3 SWAP1 SUB PUSH1 0x1F AND DUP3 ADD SWAP2 JUMPDEST POP POP POP POP POP SWAP1 POP SWAP1 JUMP JUMPDEST DUP3 DUP1 SLOAD PUSH1 0x1 DUP2 PUSH1 0x1 AND ISZERO PUSH2 0x100 MUL SUB AND PUSH1 0x2 SWAP1 DIV SWAP1 PUSH1 0x0 MSTORE PUSH1 0x20 PUSH1 0x0 KECCAK256 SWAP1 PUSH1 0x1F ADD PUSH1 0x20 SWAP1 DIV DUP2 ADD SWAP3 DUP3 PUSH1 0x1F LT PUSH2 0x4EE JUMPI DUP1 MLOAD PUSH1 0xFF NOT AND DUP4 DUP1 ADD OR DUP6 SSTORE PUSH2 0x51C JUMP JUMPDEST DUP3 DUP1 ADD PUSH1 0x1 ADD DUP6 SSTORE DUP3 ISZERO PUSH2 0x51C JUMPI SWAP2 DUP3 ADD JUMPDEST DUP3 DUP2 GT ISZERO PUSH2 0x51B JUMPI DUP3 MLOAD DUP3 SSTORE SWAP2 PUSH1 0x20 ADD SWAP2 SWAP1 PUSH1 0x1 ADD SWAP1 PUSH2 0x500 JUMP JUMPDEST JUMPDEST POP SWAP1 POP PUSH2 0x529 SWAP2 SWAP1 PUSH2 0x52D JUMP JUMPDEST POP SWAP1 JUMP JUMPDEST PUSH2 0x54F SWAP2 SWAP1 JUMPDEST DUP1 DUP3 GT ISZERO PUSH2 0x54B JUMPI PUSH1 0x0 DUP2 PUSH1 0x0 SWAP1 SSTORE POP PUSH1 0x1 ADD PUSH2 0x533 JUMP JUMPDEST POP SWAP1 JUMP JUMPDEST SWAP1 JUMP STOP LOG1 PUSH6 0x627A7A723058 KECCAK256 0xc9 0xef NUMBER 0xbf 0xc7 0xbe PUSH11 0x77DEF404C505DCD9AE4F88 LOG2 0x2c 0x2a JUMPDEST SWAP15 0xca 0xa5 DUP2 0xc6 PUSH22 0xA2993B70002900000000000000000000000000000000 \",\r\n"
            + "\t\"sourceMap\": \"476:753:0:-;;;635:75;8:9:-1;5:2;;;30:1;27;20:12;5:2;635:75:0;;;;;;;;;;;;;;;;;;;;;;;;;;;;;325:10;317:5;;:18;;;;;;;;;;;;;;;;;;694:9;683:8;:20;;;;;;;;;;;;:::i;:::-;;635:75;476:753;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;:::i;:::-;;;:::o;:::-;;;;;;;;;;;;;;;;;;;;;;;;;;;:::o;:::-;;;;;;;\"\r\n"
            + "}";

• 改成這樣

public static final String BINARY = "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";

web3j via infura in Rinkeby TestNet

超超簡略版

前言

• 傳統上乙太坊的實做為Geth，如果今天我需要連接至乙太坊的服務，及需要使用Geth
• ConsenSys提供了Infura服務，簡單講即是提供簡化的Web API接口已連接至乙太坊服務
• web3j中也有提供相關api連接

---

infura 服務

• 官方網站
• 

---

web3j 使用

1. 先建立project

   • 右上角 creat new project
   • 

2. 幫project取名

   • 重要 在下方選擇Rinkeby網路 本篇以Rinkeby測試網路為主
   • 

3. 我們需要api接口以及private key 以連接至infura

   • 

4. 我的Sample Code

import org.web3j.abi.TypeDecoder;
import org.web3j.abi.datatypes.Address;
import org.web3j.abi.datatypes.generated.Uint256;
import org.web3j.crypto.Credentials;
import org.web3j.protocol.Web3j;
import org.web3j.protocol.core.methods.request.Transaction;
import org.web3j.protocol.core.methods.response.TransactionReceipt;
import org.web3j.protocol.core.methods.response.Web3ClientVersion;
import org.web3j.protocol.http.HttpService;
import org.web3j.tx.gas.ContractGasProvider;
import org.web3j.tx.gas.StaticGasProvider;

import java.lang.reflect.Method;
import java.math.BigInteger;
import java.nio.charset.StandardCharsets;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // deploy smart contract
        Web3j web3 = Web3j.build(new HttpService("你的infura project對應的api"));
        Web3ClientVersion web3ClientVersion = web3.web3ClientVersion().send();
        System.out.println(web3ClientVersion.getWeb3ClientVersion());
        
//       Web3j web3 = Web3j.build(new  HttpService("http://127.0.0.1:7545"));
        Credentials credentials = Credentials.create("你的錢包的private key");
        ContractGasProvider provider = new StaticGasProvider(BigInteger.valueOf(20000000000L), BigInteger.valueOf(6721975L));
        SimpleStorage contract = SimpleStorage.deploy(
                web3, credentials, provider
        ).send();
        String contractAddress = contract.getContractAddress();
        System.out.println("contract Address is : "+contractAddress);
        System.out.println();
        
        
        
        //contract load
        SimpleStorage contractLoaded = SimpleStorage.load(contractAddress, web3, credentials, provider);
       
        //set a string to ethereum test net
        TransactionReceipt transactionReceipt = contractLoaded.setString("Hello World").send();
        //set a random number to test net
        int rand = new Random().nextInt(Integer.MAX_VALUE);
        contractLoaded.set(new BigInteger(String.valueOf(rand))).send();
        System.out.println("Gas Used: " + transactionReceipt.getGasUsed());
        System.out.println("transaction hash " + transactionReceipt.getTransactionHash());
        System.out.println("GetString: " + contractLoaded.getString().send());
        System.out.println(rand);
        System.out.println("Get Int: " + contractLoaded.get().send());
    
        
        
        Transaction transaction ;
        String inputData;
        
        //get transaction by transaction
        Optional<org.web3j.protocol.core.methods.response.Transaction>
                tx = web3.ethGetTransactionByHash(transactionReceipt.getTransactionHash())
                .send().getTransaction();
        
        
        System.out.println(tx);
        inputData = tx.get().getInput();
        System.out.println("input raw data = " + inputData);
        
        String testStr = new String( new BigInteger(inputData.substring(138),16).toByteArray(), "utf-8");
        System.out.println(testStr.substring(11));
        System.out.println(testStr.trim()); // remove whitespaces
        
    }
}

5. 成功執行後即可於Ethereum Explorer藉由transactionHash查詢交易細節

---

感謝Kenny's Blog的教學文 附上他的部落格連結

• (https://kennychen-blog.herokuapp.com/)