Java程序与以太坊智能合约交互

1、新建Java springboot 项目，并在pom中添加依赖

<!--web3j--><dependency><groupId>org.web3j</groupId><artifactId>core</artifactId><version>5.0.0</version></dependency><dependency><groupId>org.web3j</groupId><artifactId>codegen</artifactId><version>5.0.0</version></dependency>

2、下载官方示例代码：

https://github.com/web3j/sample-project-gradle

将Greeter.sol拷贝到Remix中，编译、deploy到自己的私有链上

3、生成合约对应的Java文件

新建“SolidityGenerateUtil”

package com.dcepsoft.eth.learn.utils;import org.web3j.codegen.SolidityFunctionWrapperGenerator;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.stream.Stream;public class SolidityGenerateUtil {// 私有实例，类初始化就加载private static SolidityGenerateUtil solidityGenerateUtil = new SolidityGenerateUtil();// 私有构造方法private SolidityGenerateUtil() {}// 公共的、静态的获取实例方法public static SolidityGenerateUtil getInstance() {return solidityGenerateUtil;}public static void genAbiAndBin(){String abi  = "[\n" +"\t{\n" +"\t\t\"constant\": false,\n" +"\t\t\"inputs\": [],\n" +"\t\t\"name\": \"kill\",\n" +"\t\t\"outputs\": [],\n" +"\t\t\"payable\": false,\n" +"\t\t\"stateMutability\": \"nonpayable\",\n" +"\t\t\"type\": \"function\"\n" +"\t},\n" +"\t{\n" +"\t\t\"constant\": false,\n" +"\t\t\"inputs\": [\n" +"\t\t\t{\n" +"\t\t\t\t\"name\": \"_greeting\",\n" +"\t\t\t\t\"type\": \"string\"\n" +"\t\t\t}\n" +"\t\t],\n" +"\t\t\"name\": \"newGreeting\",\n" +"\t\t\"outputs\": [],\n" +"\t\t\"payable\": false,\n" +"\t\t\"stateMutability\": \"nonpayable\",\n" +"\t\t\"type\": \"function\"\n" +"\t},\n" +"\t{\n" +"\t\t\"inputs\": [\n" +"\t\t\t{\n" +"\t\t\t\t\"name\": \"_greeting\",\n" +"\t\t\t\t\"type\": \"string\"\n" +"\t\t\t}\n" +"\t\t],\n" +"\t\t\"payable\": false,\n" +"\t\t\"stateMutability\": \"nonpayable\",\n" +"\t\t\"type\": \"constructor\"\n" +"\t},\n" +"\t{\n" +"\t\t\"anonymous\": false,\n" +"\t\t\"inputs\": [\n" +"\t\t\t{\n" +"\t\t\t\t\"indexed\": true,\n" +"\t\t\t\t\"name\": \"oldGreetingIdx\",\n" +"\t\t\t\t\"type\": \"string\"\n" +"\t\t\t},\n" +"\t\t\t{\n" +"\t\t\t\t\"indexed\": true,\n" +"\t\t\t\t\"name\": \"newGreetingIdx\",\n" +"\t\t\t\t\"type\": \"string\"\n" +"\t\t\t},\n" +"\t\t\t{\n" +"\t\t\t\t\"indexed\": false,\n" +"\t\t\t\t\"name\": \"oldGreeting\",\n" +"\t\t\t\t\"type\": \"string\"\n" +"\t\t\t},\n" +"\t\t\t{\n" +"\t\t\t\t\"indexed\": false,\n" +"\t\t\t\t\"name\": \"newGreeting\",\n" +"\t\t\t\t\"type\": \"string\"\n" +"\t\t\t}\n" +"\t\t],\n" +"\t\t\"name\": \"Modified\",\n" +"\t\t\"type\": \"event\"\n" +"\t},\n" +"\t{\n" +"\t\t\"constant\": true,\n" +"\t\t\"inputs\": [],\n" +"\t\t\"name\": \"greet\",\n" +"\t\t\"outputs\": [\n" +"\t\t\t{\n" +"\t\t\t\t\"name\": \"\",\n" +"\t\t\t\t\"type\": \"string\"\n" +"\t\t\t}\n" +"\t\t],\n" +"\t\t\"payable\": false,\n" +"\t\t\"stateMutability\": \"view\",\n" +"\t\t\"type\": \"function\"\n" +"\t}\n" +"]";String bin = "{\n" +"\t\"linkReferences\": {},\n" +"\t\"object\": \"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\",\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 0xda PUSH15 0x1B15856CD8A06BEA29310B90846F8F PUSH11 0xA36E963E160CA2AF0906E4 0xbe PUSH16 0x80002900000000000000000000000000 \",\n" +"\t\"sourceMap\": \"491:785:0:-;;;655:77;8:9:-1;5:2;;;30:1;27;20:12;5:2;655:77:0;;;;;;;;;;;;;;;;;;;;;;;;;;;;;334:10;326:5;;:18;;;;;;;;;;;;;;;;;;715:9;704:8;:20;;;;;;;;;;;;:::i;:::-;;655:77;491:785;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;:::i;:::-;;;:::o;:::-;;;;;;;;;;;;;;;;;;;;;;;;;;;:::o;:::-;;;;;;;\"\n" +"}";String abiFileName = "Greeter.abi";String binFileName = "Greeter.bin";generateAbiAndBin(abi,bin,abiFileName,binFileName);}public static void generateAbiAndBin(String abi,String bin,String abiFileName,String binFileName){File abiFile = new File("src/main/java/com/dcepsoft/eth/learn/contract/"+abiFileName);File binFile = new File("src/main/java/com/dcepsoft/eth/learn/contract/"+binFileName);BufferedOutputStream abiBos = null;BufferedOutputStream binBos = null;try{FileOutputStream abiFos = new FileOutputStream(abiFile);FileOutputStream binFos = new FileOutputStream(binFile);abiBos = new BufferedOutputStream(abiFos);binBos = new BufferedOutputStream(binFos);abiBos.write(abi.getBytes());abiBos.flush();binBos.write(bin.getBytes());binBos.flush();generateJavaFile(abiFile.getPath(),binFile.getPath());}catch (Exception e){e.printStackTrace();}finally {if(abiBos != null){try{abiBos.close();;}catch (IOException e){e.printStackTrace();}}if(binBos != null){try {binBos.close();}catch (IOException e){e.printStackTrace();}}}}public static void generateJavaFile(String abiFile, String binFile){String generateFile = "src/main/java/com/dcepsoft/eth/learn/contract/";generateClass(abiFile,binFile,generateFile);}public static void generateClass(String abiFile,String binFile,String generateFile){String[] args = Arrays.asList("-a",abiFile,"-b",binFile,"-p","","-o",generateFile).toArray(new String[0]);Stream.of(args).forEach(System.out::println);SolidityFunctionWrapperGenerator.main(args);}public static void main(String[] args) {genAbiAndBin();}}

使用合约编译之后的abi和二进制信息替换该类中的数据，然后执行

执行之后生成相应文件

4、Java程序调用合约执行

Springboot+web3j（4.7）+实战+填坑_一万次练习的博客-CSDN博客_web3jspringboot

package com.dcepsoft.eth.learn.handler;import com.dcepsoft.eth.learn.contract.Greeter;
import org.web3j.crypto.Credentials;
import org.web3j.protocol.Web3j;
import org.web3j.protocol.core.RemoteCall;
import org.web3j.protocol.core.methods.response.TransactionReceipt;
import org.web3j.protocol.http.HttpService;
import org.web3j.tx.Contract;
import org.web3j.tx.RawTransactionManager;
import org.web3j.tx.TransactionManager;
import org.web3j.tx.gas.StaticGasProvider;
import java.math.BigInteger;public class GreeterContractHandler {private static GreeterContractHandler contractUtil = new GreeterContractHandler();private GreeterContractHandler(){}public static GreeterContractHandler getInstance() {return contractUtil;}private static String netWorkUrl = "HTTP://127.0.0.1:7545";// 钱包私钥private static String walletKey = "0x6595b875ee20993cdf8a303395e1f037177fcb81b09f8cdf8746775687c0e6e5";// 合约地址private static String contractAddress = "0xd9145CCE52D386f254917e481eB44e9943F39138";public static void useContract(){try {//连接对应节点Web3j web3 = Web3j.build(new HttpService(netWorkUrl));Credentials credentials = Credentials.create(walletKey);TransactionManager transactionManager = new RawTransactionManager(web3, credentials,3);BigInteger gasPrice = web3.ethGasPrice().send().getGasPrice();Greeter contract = Greeter.load(contractAddress,web3,transactionManager,new StaticGasProvider(gasPrice, Contract.GAS_LIMIT));//调用合约方法RemoteCall<TransactionReceipt> setWord = contract.newGreeting("hello world");TransactionReceipt transactionReceipt = setWord.send();String transactionHash = transactionReceipt.getTransactionHash();System.out.println(transactionHash);}catch (Exception e){e.printStackTrace();}}}

其中关键一步就是

Greeter contract = Greeter.load(contractAddress,web3,transactionManager,new StaticGasProvider(gasPrice, Contract.GAS_LIMIT));

和

RemoteCall<TransactionReceipt> setWord = contract.newGreeting("hello world");

上面都是连接我们的私有节点，以及根据钱包私钥生成合约调用凭证。

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如果要下载整个以太坊区块链并保持本地节点同步.当区块链占用了我计算机上超过100GB的空间.这在台式计算机上可能有意义,但在移动设备上则不太合理. 解决此限制的一种方法是使用像Infura这样的服务. ...
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Java程序与以太坊智能合约交互

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