[web3j]java使用web3j调用以太坊私链上的智能合约

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环境


web3j命令行工具

* 这个工具可以帮我们把合约生成为一个java类,供我们实现java调用智能合约。

* github项目链接


安装4.5.5以上的新版本(4.9)


安装4.5.5以及之前的旧版本

此时的目录结构
web3j_home=/usr/local/sbin/web3j
PATH=$web3j_home/bin:$PATH
export PATH

在Maven中导入web3j

<dependency>
  <groupId>org.web3j</groupId>
  <artifactId>core</artifactId>
  <version>4.9.0</version>
</dependency>
<dependency>
  <groupId>org.web3j</groupId>
  <artifactId>core</artifactId>
  <version>4.9.0-android</version>
</dependency>

生成测试文件(java智能合约封装器)

准备sol,abi和bin文件

// SPDX-License-Identifier: SimPL-2.0
pragma solidity >=0.4.0 <=0.7.0;

contract HelloWorld {
    uint count = 2022;
    
    function setCount(uint in_count) public
    {
        count = in_count;
    }

    function GetCount()public view returns(uint)
    {
        return count;
    }
}

使用web3j把智能合约生成java类

web3j generate solidity -a hello.abi -b hello.bin -o ./web_hello -p com.coolight.hello

修改web3j自动生成的java类

    //web3j自动生成的函数
    public RemoteFunctionCall<TransactionReceipt> GetCount() {
        final Function function = new Function(
                FUNC_GETCOUNT, 
                Arrays.<Type>asList(), 
                Collections.<TypeReference<?>>emptyList());
        return executeRemoteCallTransaction(function);
    }
    //增加的函数
    public RemoteFunctionCall<BigInteger> GetCountReturn() {
        final Function function = new Function(
                FUNC_GETCOUNT,
                Collections.emptyList(),
                Arrays.asList(new TypeReference<Uint256>(){}));
        return executeRemoteCallSingleValueReturn(function, BigInteger.class);
    }
    //web3j自动生成的函数
    public RemoteFunctionCall<TransactionReceipt> getUserEvent(String user_name) 
    {
        final Function function = new Function(
                FUNC_GETUSEREVENT,
                Arrays.<Type>asList(new org.web3j.abi.datatypes.Utf8String(user_name)),
                Collections.<TypeReference<?>>emptyList());
        return executeRemoteCallTransaction(function);
    }

    //增加的函数
    public RemoteFunctionCall<String> getUserEventReturn(String user_name) {
        final Function function = new Function(
                FUNC_GETUSEREVENT,
                Arrays.asList(new org.web3j.abi.datatypes.Utf8String(user_name)),
                Arrays.asList(new TypeReference<Utf8String>(){}));
        return  executeRemoteCallSingleValueReturn(function, String.class);
    }
    //web3j自动生成的函数
    public RemoteFunctionCall<TransactionReceipt> getUserLen(String user_name) {
        final Function function = new Function(
                FUNC_GETUSERLEN,
                Arrays.<Type>asList(new org.web3j.abi.datatypes.Utf8String(user_name)),
                Collections.<TypeReference<?>>emptyList());
        return  executeRemoteCallTransaction(function);
    }

    //增加的函数
    public RemoteFunctionCall<BigInteger> getUserLenReturn(String user_name) {
        final Function function = new Function(
                FUNC_GETUSERLEN,
                Arrays.asList(new org.web3j.abi.datatypes.Utf8String(user_name)),
                Arrays.asList(new TypeReference<Uint256>(){}));
        return executeRemoteCallSingleValueReturn(function, BigInteger.class);
    }
import java.math.BigInteger;
import java.util.Arrays;
import java.util.Collections;
import org.web3j.abi.TypeReference;
import org.web3j.abi.datatypes.Function;
import org.web3j.abi.datatypes.Type;
import org.web3j.abi.datatypes.generated.Uint256;
import org.web3j.crypto.Credentials;
import org.web3j.protocol.Web3j;
import org.web3j.protocol.core.RemoteCall;
import org.web3j.protocol.core.RemoteFunctionCall;
import org.web3j.protocol.core.methods.response.TransactionReceipt;
import org.web3j.tx.Contract;
import org.web3j.tx.TransactionManager;
import org.web3j.tx.gas.ContractGasProvider;

/**
 * <p>Auto generated code.
 * <p><strong>Do not modify!</strong>
 * <p>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.
 *
 * <p>Generated with web3j version 4.5.5.
 */
@SuppressWarnings("rawtypes")
public class Hello extends Contract {
    private static final String BINARY = "{\n"
            + "\t\"linkReferences\": {},\n"
            + "\t\"object\": \"60806040526107e660005534801561001657600080fd5b5060c7806100256000396000f3fe6080604052348015600f57600080fd5b506004361060325760003560e01c80630ab93971146037578063d14e62b8146053575b600080fd5b603d607e565b6040518082815260200191505060405180910390f35b607c60048036036020811015606757600080fd5b81019080803590602001909291905050506087565b005b60008054905090565b806000819055505056fea26469706673582212205f4a89ec8a6affc1a5970dfedafa55c57435fd83a7635cd22b59193fcb6e42e964736f6c63430007000033\",\n"
            + "\t\"opcodes\": \"PUSH1 0x80 PUSH1 0x40 MSTORE PUSH2 0x7E6 PUSH1 0x0 SSTORE CALLVALUE DUP1 ISZERO PUSH2 0x16 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH1 0xC7 DUP1 PUSH2 0x25 PUSH1 0x0 CODECOPY PUSH1 0x0 RETURN INVALID PUSH1 0x80 PUSH1 0x40 MSTORE CALLVALUE DUP1 ISZERO PUSH1 0xF JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST POP PUSH1 0x4 CALLDATASIZE LT PUSH1 0x32 JUMPI PUSH1 0x0 CALLDATALOAD PUSH1 0xE0 SHR DUP1 PUSH4 0xAB93971 EQ PUSH1 0x37 JUMPI DUP1 PUSH4 0xD14E62B8 EQ PUSH1 0x53 JUMPI JUMPDEST PUSH1 0x0 DUP1 REVERT JUMPDEST PUSH1 0x3D PUSH1 0x7E JUMP JUMPDEST PUSH1 0x40 MLOAD DUP1 DUP3 DUP2 MSTORE PUSH1 0x20 ADD SWAP2 POP POP PUSH1 0x40 MLOAD DUP1 SWAP2 SUB SWAP1 RETURN JUMPDEST PUSH1 0x7C PUSH1 0x4 DUP1 CALLDATASIZE SUB PUSH1 0x20 DUP2 LT ISZERO PUSH1 0x67 JUMPI PUSH1 0x0 DUP1 REVERT JUMPDEST DUP2 ADD SWAP1 DUP1 DUP1 CALLDATALOAD SWAP1 PUSH1 0x20 ADD SWAP1 SWAP3 SWAP2 SWAP1 POP POP POP PUSH1 0x87 JUMP JUMPDEST STOP JUMPDEST PUSH1 0x0 DUP1 SLOAD SWAP1 POP SWAP1 JUMP JUMPDEST DUP1 PUSH1 0x0 DUP2 SWAP1 SSTORE POP POP JUMP INVALID LOG2 PUSH5 0x6970667358 0x22 SLT KECCAK256 0x5F 0x4A DUP10 0xEC DUP11 PUSH11 0xFFC1A5970DFEDAFA55C574 CALLDATALOAD REVERT DUP4 0xA7 PUSH4 0x5CD22B59 NOT EXTCODEHASH 0xCB PUSH15 0x42E964736F6C634300070000330000 \",\n"
            + "\t\"sourceMap\": \"75:231:0:-:0;;;115:4;102:17;;75:231;;;;;;;;;;;;;;;;\"\n"
            + "}\n";

    public static final String FUNC_GETCOUNT = "GetCount";

    public static final String FUNC_SETCOUNT = "setCount";

    @Deprecated
    protected Hello(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {
        super(BINARY, contractAddress, web3j, credentials, gasPrice, gasLimit);
    }

    protected Hello(String contractAddress, Web3j web3j, Credentials credentials, ContractGasProvider contractGasProvider) {
        super(BINARY, contractAddress, web3j, credentials, contractGasProvider);
    }

    @Deprecated
    protected Hello(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
        super(BINARY, contractAddress, web3j, transactionManager, gasPrice, gasLimit);
    }

    protected Hello(String contractAddress, Web3j web3j, TransactionManager transactionManager, ContractGasProvider contractGasProvider) {
        super(BINARY, contractAddress, web3j, transactionManager, contractGasProvider);
    }

    public RemoteFunctionCall<TransactionReceipt> GetCount() {
        final Function function = new Function(
                FUNC_GETCOUNT, 
                Arrays.<Type>asList(), 
                Collections.<TypeReference<?>>emptyList());
        return executeRemoteCallTransaction(function);
    }

    // 新增获取返回值方法
    public RemoteFunctionCall<BigInteger> GetCountReturn() {
        final Function function = new Function(
                FUNC_GETCOUNT, 
                Collections.emptyList(),
                Arrays.asList(new TypeReference<Uint256>(){}));
        return executeRemoteCallSingleValueReturn(function, BigInteger.class);
    }

    public RemoteFunctionCall<TransactionReceipt> setCount(BigInteger in_count) {
        final Function function = new Function(
                FUNC_SETCOUNT, 
                Arrays.<Type>asList(new org.web3j.abi.datatypes.generated.Uint256(in_count)), 
                Collections.<TypeReference<?>>emptyList());
        return executeRemoteCallTransaction(function);
    }

    @Deprecated
    public static Hello load(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {
        return new Hello(contractAddress, web3j, credentials, gasPrice, gasLimit);
    }

    @Deprecated
    public static Hello load(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
        return new Hello(contractAddress, web3j, transactionManager, gasPrice, gasLimit);
    }

    public static Hello load(String contractAddress, Web3j web3j, Credentials credentials, ContractGasProvider contractGasProvider) {
        return new Hello(contractAddress, web3j, credentials, contractGasProvider);
    }

    public static Hello load(String contractAddress, Web3j web3j, TransactionManager transactionManager, ContractGasProvider contractGasProvider) {
        return new Hello(contractAddress, web3j, transactionManager, contractGasProvider);
    }

    public static RemoteCall<Hello> deploy(Web3j web3j, Credentials credentials, ContractGasProvider contractGasProvider) {
        return deployRemoteCall(Hello.class, web3j, credentials, contractGasProvider, BINARY, "");
    }

    @Deprecated
    public static RemoteCall<Hello> deploy(Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {
        return deployRemoteCall(Hello.class, web3j, credentials, gasPrice, gasLimit, BINARY, "");
    }

    public static RemoteCall<Hello> deploy(Web3j web3j, TransactionManager transactionManager, ContractGasProvider contractGasProvider) {
        return deployRemoteCall(Hello.class, web3j, transactionManager, contractGasProvider, BINARY, "");
    }

    @Deprecated
    public static RemoteCall<Hello> deploy(Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
        return deployRemoteCall(Hello.class, web3j, transactionManager, gasPrice, gasLimit, BINARY, "");
    }
}

测试调用智能合约

import java.math.BigInteger;

import org.web3j.crypto.Credentials;
import org.web3j.crypto.RawTransaction;
import org.web3j.crypto.TransactionEncoder;
import org.web3j.crypto.WalletUtils;
import org.web3j.protocol.Web3j;
import org.web3j.protocol.admin.Admin;
import org.web3j.protocol.admin.methods.response.PersonalUnlockAccount;
import org.web3j.protocol.core.DefaultBlockParameterName;
import org.web3j.protocol.core.methods.response.EthGetBalance;
import org.web3j.protocol.core.methods.response.EthGetTransactionCount;
import org.web3j.protocol.core.methods.response.EthSendTransaction;
import org.web3j.protocol.core.methods.response.TransactionReceipt;
import org.web3j.protocol.http.HttpService;
import org.web3j.tx.RawTransactionManager;
import org.web3j.tx.TransactionManager;
import org.web3j.tx.gas.ContractGasProvider;
import org.web3j.tx.gas.StaticGasProvider;
import org.web3j.utils.Convert;
import org.web3j.utils.Numeric;

public class App
{
   // 1 - 智能合约地址
   private static String contractAddress = "0x62f7ca98490B199857ccDf9e68C218DEf5000d50";

    //燃料消耗
    private static final BigInteger gasPrice = new BigInteger("100000");

    //消耗限制
    private static final BigInteger gasLimit = new BigInteger("300000");

    //2 - 私链ID
    private static final long chainId = 7;


   // main method
   public static void main(String[] args) {

        //3 - 私钥的文件名
        String fileName = "UTC--2022-01-22T14-43-04.829667987Z--7cbad9dbed1f3ef418de1f0c6412cfec197c7751";
        try{
        // 4 - 加载 web3j - 这里需要修改为你要连接的节点链接
       Web3j web3 = Web3j.build(new HttpService("http://localhost:8545/"));

        // 5 - 加载账号 - 第一个String是密码,第二个是私钥的文件路径
       Credentials credentials = WalletUtils.loadCredentials("123456", "/home/0Acoolight/geth/rungeth/data/keystore/" + fileName);
       // 6 - 加载合约
       Hello contract = Hello.load(
           contractAddress, web3,
           new RawTransactionManager(web3, credentials, chainId),
           new StaticGasProvider(gasPrice, gasLimit)
       );
       // say hello
       System.out.println("Welcome coolight - " + credentials.getAddress());
       // 7 - 调用智能合约
           BigInteger currentValue;
           // 获取Count的值 - 调用GetCountReturn() 相当于合约中的GetCount()
           currentValue = contract.GetCountReturn().send();
           System.out.println(currentValue);
           // 修改Count的值 - 调用setCount()
           contract.setCount(new BigInteger("1")).send();
           // 获取Count的值
           currentValue = contract.GetCountReturn().send();
           System.out.println(currentValue);
       } catch (Exception e) {
           e.printStackTrace();
       }
   }
}

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