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web3j基本使用

發布時間：2024/1/1 编程问答 42 豆豆

生活随笔收集整理的這篇文章主要介紹了 web3j基本使用小編覺得挺不錯的,現在分享給大家,幫大家做個參考.

編譯生成javaBean對象

編寫solidity程序，保存在Voting.sol文件中

pragma solidity ^0.4.22;contract Voting{bytes32[] public candidateList;mapping(bytes32=>uint8) public votingMap;constructor(bytes32[] candidateListName) public{candidateList = candidateListName;}function validateCandidate(bytes32 candidateListName) internal view returns(bool){for(uint8 i=0 ; i<candidateList.length ; i++){if(candidateListName == candidateList[i]){return true;}}return false;}function vote(bytes32 candidateListName) public{require(validateCandidate(candidateListName));votingMap[candidateListName] += 1;}function totalVoters(bytes32 candidateListName) public view returns(uint8){require(validateCandidate(candidateListName));return votingMap[candidateListName];} }

編譯sol文件，生成bin和abi文件

./node_modules/solc/solcjs Voting.sol --bin --abi --optimize -o sourceCode

使用web3j編譯生成javaBean類，將生成的文件加入到java的項目中

web3j solidity generate sourceCode/Voting_sol_Voting.bin sourceCode/Voting_sol_Voting.abi -o ./javaAPI -p com.yqj.blockChain

部署私鏈

geth --networkid 123 --rpc --rpcaddr 192.168.1.114 --rpcport 8989 --port 3000 --dev --datadir data1 console

編寫java程序測試web3j

導包

測試連接情況

@Slf4j(topic = "c.BlockChainTest") public class BlockChainTest {public static void main(String[] args) throws IOException {Web3j web3 = Web3j.build(new HttpService("http://192.168.1.114:8989"));Web3ClientVersion web3ClientVersion = web3.web3ClientVersion().send();String clientVersion = web3ClientVersion.getWeb3ClientVersion();log.debug("{}",clientVersion);} }

輸出結果：

19:14:34 [main] c.BlockChainTest - Geth/v1.8.17-stable/linux-amd64/go1.9.7Process finished with exit code 0

合約部署與方法調用

測試文件 BlockChainTest

package com.yqj.blockchain;import lombok.extern.slf4j.Slf4j; import org.web3j.crypto.Credentials; import org.web3j.crypto.WalletUtils; import org.web3j.protocol.Web3j; import org.web3j.protocol.core.methods.response.Web3ClientVersion; import org.web3j.protocol.http.HttpService; import org.web3j.utils.Numeric;import java.math.BigInteger; import java.util.ArrayList; import java.util.Collections; import java.util.List;@Slf4j(topic = "c.BlockChainTest") public class BlockChainTest {public static void main(String[] args) throws Exception {loadContract();}//加載已經在鏈上的合約，并且調用方法public static void loadContract() throws Exception {//建立私鏈連接Web3j web3j = Web3j.build(new HttpService("http://192.168.1.114:8989"));//加載錢包賬戶,需要從geth的data文件中拷貝出來keysotre文件夾里的內容Credentials credentials = WalletUtils.loadCredentials("", "D:\\study\\code\\blockchain\\java-blockchain\\target\\classes\\keystore\\UTC--2020-05-23T13-30-20.410109802Z--613d104e6d80ce5a06e7987d39bbd4ee0ccd7656");//加載合約String contractAddr = "0x0db5bd6503e820be1691760491fd83df3ede3d76";Voting_sol_Voting contract = Voting_sol_Voting.load(contractAddr, web3j, credentials, BigInteger.valueOf(3000000), BigInteger.valueOf(3000000));log.debug("{}",contract);String count = contract.totalVoters(stringToBytes("Alice")).send().toString();log.debug("{}",count);contract.vote(stringToBytes("Alice")).send();count = contract.totalVoters(stringToBytes("Alice")).send().toString();log.debug("{}",count);}//部署合約public static void createContract() throws Exception {//建立私鏈連接Web3j web3j = Web3j.build(new HttpService("http://192.168.1.114:8989"));//查看版本信息，驗證是否連接成功Web3ClientVersion web3ClientVersion = web3j.web3ClientVersion().send();String clientVersion = web3ClientVersion.getWeb3ClientVersion();log.debug("{}",clientVersion);//加載錢包賬戶Credentials credentials = WalletUtils.loadCredentials("", "D:\\study\\code\\blockchain\\java-blockchain\\target\\classes\\keystore\\UTC--2020-05-23T13-30-20.410109802Z--613d104e6d80ce5a06e7987d39bbd4ee0ccd7656");log.debug("{}",credentials);//構建初始化參數List<byte[]> list = new ArrayList<>();list.add(stringToBytes("Alice"));list.add(stringToBytes("Bob"));list.add(stringToBytes("Jerry"));//部署合約Voting_sol_Voting voting = Voting_sol_Voting.deploy(web3j,credentials,BigInteger.valueOf(3000000),BigInteger.valueOf(3000000),list).send();//合約地址 0x0db5bd6503e820be1691760491fd83df3ede3d76log.debug("{}",voting.getContractAddress());}//將字符串轉換為可以轉換為bytes32的形式的byte[]public static byte[] stringToBytes(String asciiValue){char[] chars = asciiValue.toCharArray();StringBuffer hex = new StringBuffer();for (int i = 0; i < chars.length; i++) {hex.append(Integer.toHexString((int) chars[i]));}String hexString = hex.toString() + "".join("", Collections.nCopies(32 - (hex.length()/2), "00"));return Numeric.hexStringToByteArray(hexString);} }

由web3j自動生成的文件 Voting_sol_Voting

package com.yqj.blockchain;import java.math.BigInteger; import java.util.Arrays; import java.util.Collections; import java.util.List; import org.web3j.abi.FunctionEncoder; import org.web3j.abi.TypeReference; import org.web3j.abi.datatypes.Function; import org.web3j.abi.datatypes.Type; import org.web3j.abi.datatypes.generated.Bytes32; import org.web3j.abi.datatypes.generated.Uint8; 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.tx.Contract; import org.web3j.tx.TransactionManager; import org.web3j.tx.gas.ContractGasProvider;/*** Auto generated code.* Do not modify!* Please use the <a href="https://docs.web3j.io/command_line.html">web3j command line tools</a>,* or the org.web3j.codegen.SolidityFunctionWrapperGenerator in the * <a href="https://github.com/web3j/web3j/tree/master/codegen">codegen module</a> to update.** Generated with web3j version 3.6.0.*/ public class Voting_sol_Voting extends Contract {private static final String BINARY = "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";public static final String FUNC_VOTINGMAP = "votingMap";public static final String FUNC_TOTALVOTERS = "totalVoters";public static final String FUNC_VOTE = "vote";public static final String FUNC_CANDIDATELIST = "candidateList";@Deprecatedprotected Voting_sol_Voting(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {super(BINARY, contractAddress, web3j, credentials, gasPrice, gasLimit);}protected Voting_sol_Voting(String contractAddress, Web3j web3j, Credentials credentials, ContractGasProvider contractGasProvider) {super(BINARY, contractAddress, web3j, credentials, contractGasProvider);}@Deprecatedprotected Voting_sol_Voting(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {super(BINARY, contractAddress, web3j, transactionManager, gasPrice, gasLimit);}protected Voting_sol_Voting(String contractAddress, Web3j web3j, TransactionManager transactionManager, ContractGasProvider contractGasProvider) {super(BINARY, contractAddress, web3j, transactionManager, contractGasProvider);}public RemoteCall<BigInteger> votingMap(byte[] param0) {final Function function = new Function(FUNC_VOTINGMAP, Arrays.<Type>asList(new Bytes32(param0)),Arrays.<TypeReference<?>>asList(new TypeReference<Uint8>() {}));return executeRemoteCallSingleValueReturn(function, BigInteger.class);}public RemoteCall<BigInteger> totalVoters(byte[] candidateListName) {final Function function = new Function(FUNC_TOTALVOTERS, Arrays.<Type>asList(new Bytes32(candidateListName)),Arrays.<TypeReference<?>>asList(new TypeReference<Uint8>() {}));return executeRemoteCallSingleValueReturn(function, BigInteger.class);}public RemoteCall<TransactionReceipt> vote(byte[] candidateListName) {final Function function = new Function(FUNC_VOTE, Arrays.<Type>asList(new Bytes32(candidateListName)),Collections.<TypeReference<?>>emptyList());return executeRemoteCallTransaction(function);}public RemoteCall<byte[]> candidateList(BigInteger param0) {final Function function = new Function(FUNC_CANDIDATELIST, Arrays.<Type>asList(new org.web3j.abi.datatypes.generated.Uint256(param0)), Arrays.<TypeReference<?>>asList(new TypeReference<Bytes32>() {}));return executeRemoteCallSingleValueReturn(function, byte[].class);}public static RemoteCall<Voting_sol_Voting> deploy(Web3j web3j, Credentials credentials, ContractGasProvider contractGasProvider, List<byte[]> candidateListName) {String encodedConstructor = FunctionEncoder.encodeConstructor(Arrays.<Type>asList(new org.web3j.abi.datatypes.DynamicArray<Bytes32>(org.web3j.abi.Utils.typeMap(candidateListName, Bytes32.class))));return deployRemoteCall(Voting_sol_Voting.class, web3j, credentials, contractGasProvider, BINARY, encodedConstructor);}public static RemoteCall<Voting_sol_Voting> deploy(Web3j web3j, TransactionManager transactionManager, ContractGasProvider contractGasProvider, List<byte[]> candidateListName) {String encodedConstructor = FunctionEncoder.encodeConstructor(Arrays.<Type>asList(new org.web3j.abi.datatypes.DynamicArray<Bytes32>(org.web3j.abi.Utils.typeMap(candidateListName, Bytes32.class))));return deployRemoteCall(Voting_sol_Voting.class, web3j, transactionManager, contractGasProvider, BINARY, encodedConstructor);}@Deprecatedpublic static RemoteCall<Voting_sol_Voting> deploy(Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit, List<byte[]> candidateListName) {String encodedConstructor = FunctionEncoder.encodeConstructor(Arrays.<Type>asList(new org.web3j.abi.datatypes.DynamicArray<Bytes32>(org.web3j.abi.Utils.typeMap(candidateListName, Bytes32.class))));return deployRemoteCall(Voting_sol_Voting.class, web3j, credentials, gasPrice, gasLimit, BINARY, encodedConstructor);}@Deprecatedpublic static RemoteCall<Voting_sol_Voting> deploy(Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit, List<byte[]> candidateListName) {String encodedConstructor = FunctionEncoder.encodeConstructor(Arrays.<Type>asList(new org.web3j.abi.datatypes.DynamicArray<Bytes32>(org.web3j.abi.Utils.typeMap(candidateListName, Bytes32.class))));return deployRemoteCall(Voting_sol_Voting.class, web3j, transactionManager, gasPrice, gasLimit, BINARY, encodedConstructor);}@Deprecatedpublic static Voting_sol_Voting load(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {return new Voting_sol_Voting(contractAddress, web3j, credentials, gasPrice, gasLimit);}@Deprecatedpublic static Voting_sol_Voting load(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {return new Voting_sol_Voting(contractAddress, web3j, transactionManager, gasPrice, gasLimit);}public static Voting_sol_Voting load(String contractAddress, Web3j web3j, Credentials credentials, ContractGasProvider contractGasProvider) {return new Voting_sol_Voting(contractAddress, web3j, credentials, contractGasProvider);}public static Voting_sol_Voting load(String contractAddress, Web3j web3j, TransactionManager transactionManager, ContractGasProvider contractGasProvider) {return new Voting_sol_Voting(contractAddress, web3j, transactionManager, contractGasProvider);} }

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