java如何監聽以太坊交易

時間  2019-11-12
標籤 java 如何 監聽 以太 交易 欄目 Java 简体版
原文   原文鏈接

你能夠在web3j庫的幫助下使用java輕鬆監聽以太坊交易，但此庫沒法監聽Erc20 Token交易。html

要監聽Erc20Token交易，你必須使用在合約（token）建立時的token封裝類。我假設你已經使用最少的功能部署了合約，所以你的封裝類看起來像這樣：java

package com.bolenum.util;

import java.io.IOException;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util...;

import org.web3j.abi.EventEncoder;
import org.web3j.abi...
import org.web3j.crypto.Credentials;
import org.web3j.protocol.Web3j;
import org.web3j.protocol...;
import org.web3j.tx.Contract;
import org.web3j.tx.TransactionManager;

import rx.Observable;
import rx.functions.Func1;

...

public final class Erc20TokenWrapper extends Contract {

    private static final String BINARY = "contract binary key";

    private Erc20TokenWrapper(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {
        super(BINARY, contractAddress, web3j, credentials, gasPrice, gasLimit);
    }

    private Erc20TokenWrapper(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
        super(BINARY, contractAddress, web3j, transactionManager, gasPrice, gasLimit);
    }

    public List<TransferEventResponse> getTransferEvents(TransactionReceipt transactionReceipt) {
        ...
        return responses;
    }

    public Observable<TransferEventResponse> transferEventObservable(DefaultBlockParameter startBlock, DefaultBlockParameter endBlock) {
		...
	}

	...
	
    public Uint256 balanceOf(Address _owner) throws IOException {
        Function function = new Function("balanceOf", 
                Arrays.<Type>asList(_owner), 
                Arrays.<TypeReference<?>>asList(new TypeReference<Uint256>() {}));
        return executeCallSingleValueReturn(function);
    }

	...
	
    public TransactionReceipt transfer(Address _to, Uint256 _amount) throws IOException, TransactionException {
        Function function = new Function("transfer", Arrays.<Type>asList(_to, _amount), Collections.<TypeReference<?>>emptyList());
        return executeTransaction(function);
    }

    ...
   
    public static Erc20TokenWrapper load(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
        return new Erc20TokenWrapper(contractAddress, web3j, transactionManager, gasPrice, gasLimit);
    }

    public static class TransferEventResponse {
        public Address _from;
        public Address _to;
        public Uint256 _value;
        public String _transactionHash;
    }
	
	...
}

如今你必須使用這個類函數來加載合約而後監聽交易。使用下面的代碼加載和監聽交易：android

Web3j web3j = Web3j.build(new HttpService("url of your ethereum blockchain"))    
ClientTransactionManager transactionManager = new ClientTransactionManager(web3j,
                    "your deployed contract addess");
            Erc20TokenWrapper token = Erc20TokenWrapper.load("your deployed contract addess", web3j, transactionManager,
                    Contract.GAS_PRICE, Contract.GAS_LIMIT);
            token.transferEventObservable(DefaultBlockParameterName.EARLIEST, DefaultBlockParameterName.LATEST)
                    .subscribe(tx -> {
                                   String toAddress = tx._to.getValue();
                                   String fromAddress = tx._from.getValue();
                                   String txHash = tx._transactionHash.getValue();
                               }

若是你已經部署了合約，它由第三人部署，那麼你能夠直接使用個人包裝類，只需更改你能夠從https://etherscan.io/tokens很容易得到的二進制密鑰。程序員

結論：所以你能夠將此代碼用於任何token的監聽交易。此代碼爲你提供address，fromAddress和transactionHash。因此這些東西你能夠根據你的要求使用，你能夠將它們保存在你的數據庫中，或者你只保存地址是你的錢包地址的交易。web

謝謝，我但願這會有所幫助。數據庫

若是但願快速進行web3j、java、以太坊開發，那請看咱們精心打造的教程： java以太坊開發教程，主要是針對java和android程序員進行區塊鏈以太坊開發的web3j詳解。app

這裏是原文ide

完整代碼以下：函數

package com.bolenum.util;

import java.io.IOException;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.Future;

import org.web3j.abi.EventEncoder;
import org.web3j.abi.EventValues;
import org.web3j.abi.FunctionEncoder;
import org.web3j.abi.TypeReference;
import org.web3j.abi.datatypes.Address;
import org.web3j.abi.datatypes.Event;
import org.web3j.abi.datatypes.Function;
import org.web3j.abi.datatypes.Type;
import org.web3j.abi.datatypes.Utf8String;
import org.web3j.abi.datatypes.generated.Uint256;
import org.web3j.abi.datatypes.generated.Uint8;
import org.web3j.crypto.Credentials;
import org.web3j.protocol.Web3j;
import org.web3j.protocol.core.DefaultBlockParameter;
import org.web3j.protocol.core.RemoteCall;
import org.web3j.protocol.core.methods.request.EthFilter;
import org.web3j.protocol.core.methods.response.Log;
import org.web3j.protocol.core.methods.response.TransactionReceipt;
import org.web3j.protocol.exceptions.TransactionException;
import org.web3j.tx.Contract;
import org.web3j.tx.TransactionManager;

import rx.Observable;
import rx.functions.Func1;

/**
 * Auto generated code.<br>
 * <strong>Do not modify!</strong><br>
 * Please use the <a href="https://docs.web3j.io/command_line.html">web3j command line tools</a>, or {@link org.web3j.codegen.SolidityFunctionWrapperGenerator} to update.
 *
 * <p>Generated with web3j version 2.3.1.
 */
public final class Erc20TokenWrapper extends Contract {

    private static final String BINARY = "contract binary key";

    private Erc20TokenWrapper(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {
        super(BINARY, contractAddress, web3j, credentials, gasPrice, gasLimit);
    }

    private Erc20TokenWrapper(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
        super(BINARY, contractAddress, web3j, transactionManager, gasPrice, gasLimit);
    }

    public List<TransferEventResponse> getTransferEvents(TransactionReceipt transactionReceipt) {
        final Event event = new Event("Transfer", 
                Arrays.<TypeReference<?>>asList(new TypeReference<Address>() {}, new TypeReference<Address>() {}),
                Arrays.<TypeReference<?>>asList(new TypeReference<Uint256>() {}));
        List<EventValues> valueList = extractEventParameters(event, transactionReceipt);
        ArrayList<TransferEventResponse> responses = new ArrayList<TransferEventResponse>(valueList.size());
        for (EventValues eventValues : valueList) {
            TransferEventResponse typedResponse = new TransferEventResponse();
            typedResponse._from = (Address) eventValues.getIndexedValues().get(0);
            typedResponse._to = (Address) eventValues.getIndexedValues().get(1);
            typedResponse._value = (Uint256) eventValues.getNonIndexedValues().get(0);
            responses.add(typedResponse);
        }
        return responses;
    }

    public Observable<TransferEventResponse> transferEventObservable(DefaultBlockParameter startBlock, DefaultBlockParameter endBlock) {
        final Event event = new Event("Transfer", 
                Arrays.<TypeReference<?>>asList(new TypeReference<Address>() {}, new TypeReference<Address>() {}),
                Arrays.<TypeReference<?>>asList(new TypeReference<Uint256>() {}));
        EthFilter filter = new EthFilter(startBlock, endBlock, getContractAddress());
        filter.addSingleTopic(EventEncoder.encode(event));
        return web3j.ethLogObservable(filter).map(new Func1<Log, TransferEventResponse>() {
            @Override
            public TransferEventResponse call(Log log) {
                EventValues eventValues = extractEventParameters(event, log);
                TransferEventResponse typedResponse = new TransferEventResponse();
                typedResponse._from = (Address) eventValues.getIndexedValues().get(0);
                typedResponse._to = (Address) eventValues.getIndexedValues().get(1);
                typedResponse._value = (Uint256) eventValues.getNonIndexedValues().get(0);
                typedResponse._transactionHash = log.getTransactionHash();
                return typedResponse;
            }
        });
    }

    public List<ApprovalEventResponse> getApprovalEvents(TransactionReceipt transactionReceipt) {
        final Event event = new Event("Approval", 
                Arrays.<TypeReference<?>>asList(new TypeReference<Address>() {}, new TypeReference<Address>() {}),
                Arrays.<TypeReference<?>>asList(new TypeReference<Uint256>() {}));
        List<EventValues> valueList = extractEventParameters(event, transactionReceipt);
        ArrayList<ApprovalEventResponse> responses = new ArrayList<ApprovalEventResponse>(valueList.size());
        for (EventValues eventValues : valueList) {
            ApprovalEventResponse typedResponse = new ApprovalEventResponse();
            typedResponse._owner = (Address) eventValues.getIndexedValues().get(0);
            typedResponse._spender = (Address) eventValues.getIndexedValues().get(1);
            typedResponse._value = (Uint256) eventValues.getNonIndexedValues().get(0);
            responses.add(typedResponse);
        }
        return responses;
    }

    public Observable<ApprovalEventResponse> approvalEventObservable(DefaultBlockParameter startBlock, DefaultBlockParameter endBlock) {
        final Event event = new Event("Approval", 
                Arrays.<TypeReference<?>>asList(new TypeReference<Address>() {}, new TypeReference<Address>() {}),
                Arrays.<TypeReference<?>>asList(new TypeReference<Uint256>() {}));
        EthFilter filter = new EthFilter(startBlock, endBlock, getContractAddress());
        filter.addSingleTopic(EventEncoder.encode(event));
        return web3j.ethLogObservable(filter).map(new Func1<Log, ApprovalEventResponse>() {
            @Override
            public ApprovalEventResponse call(Log log) {
                EventValues eventValues = extractEventParameters(event, log);
                ApprovalEventResponse typedResponse = new ApprovalEventResponse();
                typedResponse._owner = (Address) eventValues.getIndexedValues().get(0);
                typedResponse._spender = (Address) eventValues.getIndexedValues().get(1);
                typedResponse._value = (Uint256) eventValues.getNonIndexedValues().get(0);
                typedResponse._transactionHash = log.getTransactionHash();
                return typedResponse;
            }
        });
    }

    public Future<Utf8String> name() throws IOException {
        Function function = new Function("name", 
                Arrays.<Type>asList(), 
                Arrays.<TypeReference<?>>asList(new TypeReference<Utf8String>() {}));
        return executeCallSingleValueReturn(function);
    }

    public TransactionReceipt approve(Address _spender, Uint256 _amount) throws IOException, TransactionException {
        Function function = new Function("approve", Arrays.<Type>asList(_spender, _amount), Collections.<TypeReference<?>>emptyList());
        return executeTransaction(function);
    }

    public Future<Uint256> totalSupply() throws IOException {
        Function function = new Function("totalSupply", 
                Arrays.<Type>asList(), 
                Arrays.<TypeReference<?>>asList(new TypeReference<Uint256>() {}));
        return executeCallSingleValueReturn(function);
    }

    public TransactionReceipt transferFrom(Address _from, Address _to, Uint256 _amount) throws IOException, TransactionException {
        Function function = new Function("transferFrom", Arrays.<Type>asList(_from, _to, _amount), Collections.<TypeReference<?>>emptyList());
        return  executeTransaction(function);
    }

    public Uint8 decimals() throws IOException {
        Function function = new Function("decimals", 
                Arrays.<Type>asList(), 
                Arrays.<TypeReference<?>>asList(new TypeReference<Uint8>() {}));
        return executeCallSingleValueReturn(function);
    }

    public Uint256 balanceOf(Address _owner) throws IOException {
        Function function = new Function("balanceOf", 
                Arrays.<Type>asList(_owner), 
                Arrays.<TypeReference<?>>asList(new TypeReference<Uint256>() {}));
        return executeCallSingleValueReturn(function);
    }

    public Future<Address> owner() throws IOException {
        Function function = new Function("owner", 
                Arrays.<Type>asList(), 
                Arrays.<TypeReference<?>>asList(new TypeReference<Address>() {}));
        return executeCallSingleValueReturn(function);
    }

    public Future<Utf8String> symbol() throws IOException {
        Function function = new Function("symbol", 
                Arrays.<Type>asList(), 
                Arrays.<TypeReference<?>>asList(new TypeReference<Utf8String>() {}));
        return executeCallSingleValueReturn(function);
    }

    public TransactionReceipt transfer(Address _to, Uint256 _amount) throws IOException, TransactionException {
        Function function = new Function("transfer", Arrays.<Type>asList(_to, _amount), Collections.<TypeReference<?>>emptyList());
        return executeTransaction(function);
    }

    public Future<Uint256> allowance(Address _owner, Address _spender) throws IOException {
        Function function = new Function("allowance", 
                Arrays.<Type>asList(_owner, _spender), 
                Arrays.<TypeReference<?>>asList(new TypeReference<Uint256>() {}));
        return executeCallSingleValueReturn(function);
    }

    public static RemoteCall<Erc20TokenWrapper> deploy(Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit, BigInteger initialWeiValue, Uint256 totalSupply, Utf8String tokenName, Uint8 decimalUnits, Utf8String tokenSymbol) {
        String encodedConstructor = FunctionEncoder.encodeConstructor(Arrays.<Type>asList(totalSupply, tokenName, decimalUnits, tokenSymbol));
        return deployRemoteCall(Erc20TokenWrapper.class, web3j, credentials, gasPrice, gasLimit, BINARY, encodedConstructor, initialWeiValue);
    }

    public static RemoteCall<Erc20TokenWrapper> deploy(Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit, BigInteger initialWeiValue, Uint256 totalSupply, Utf8String tokenName, Uint8 decimalUnits, Utf8String tokenSymbol) {
        String encodedConstructor = FunctionEncoder.encodeConstructor(Arrays.<Type>asList(totalSupply, tokenName, decimalUnits, tokenSymbol));
        return deployRemoteCall(Erc20TokenWrapper.class, web3j, transactionManager, gasPrice, gasLimit, BINARY, encodedConstructor, initialWeiValue);
    }

    public static Erc20TokenWrapper load(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {
        return new Erc20TokenWrapper(contractAddress, web3j, credentials, gasPrice, gasLimit);
    }

    public static Erc20TokenWrapper load(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
        return new Erc20TokenWrapper(contractAddress, web3j, transactionManager, gasPrice, gasLimit);
    }

    public static class TransferEventResponse {
        public Address _from;

        public Address _to;

        public Uint256 _value;

        public String _transactionHash;
    }

    public static class ApprovalEventResponse {
        public Address _owner;

        public Address _spender;

        public Uint256 _value;

        public String _transactionHash;
    }
}
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