web3j|java开发以太坊---不搭节点开发以太坊|java

java开发以太坊---不搭节点开发

readme
直接上代码

readme 以太坊区块链浏览器有提供官方api 已经满足了基本开发需求
api连接
优点：可以不用搭建节点，节省内存，无须担心节点挂掉影响业务
缺点：官方限制请求接口频率最高为每秒为5次/ip地址，无法像节点一样监听，需要跑定时任务去查询新的交易
之前写过了搭节点开发的教程细节和概念不想再说一遍了直接上代码
交易功能和搭节点有点差别这里是构建交易→离线签名→编码→用api接口广播
需要注意的是getTranNum接口有一点不同还有因为接口请求频率原因需要加锁及线程休眠的手段来控制频率这里没有去做自行处理
maven和jar包去之前的博客的3（web3j引入）看，一毛一样不想再写一次有不懂的也可以看一下
直接上代码接口

package com.lim.service; import com.alibaba.fastjson.JSONObject; import java.math.BigInteger; public interface IAccountService {/** * 离线创建账户 * @param pwd * @return */ JSONObject createAccount(String pwd); /** * 获取当前gasPrice * @return */ JSONObject getGasPrice() throws Exception; /** * 检查交易状态 0-正常 1-交易错误 * @param hash * @return * @throws Exception */ String checkTran(String hash) throws Exception; /** * 检查交易pending状态 0-失败 1-已完成 null/umpty-pending中 * @return * @throws Exception */ String checkTranPending(String hash) throws Exception; /** * 获取地址的交易数量 * @param address * @return * @throws Exception */ BigInteger getTranNum(String address) throws Exception; /** * 获取账户eth余额 * @param address * @return */ String getEthBalance(String address) throws Exception; /** * 获取账户usdt余额 * @param address * @return */ String getUsdtBalance(String address) throws Exception; /** * eth交易 * @param from * @param to * @param privateKey * @param num * @param gasPrice * @param nonce * @return * @throws Exception */ JSONObject tranEth(String from, String to, String privateKey, String num, String gasPrice, String nonce) throws Exception; /** * usdt交易 * @param from * @param to * @param privateKey * @param num * @param gasPrice * @param gaslimit * @param nonce * @return */ JSONObject tranUsdt(String from, String to, String privateKey, String num, String gasPrice, String gaslimit, String nonce)throws Exception; }

实现类

package com.lim.service.impl; import com.alibaba.fastjson.JSONObject; import com.lim.eth.EthConstant; import com.lim.redis.IRedisService; import com.lim.service.IAccountService; import com.lim.util.HttpUtils; import io.github.novacrypto.bip39.MnemonicGenerator; import io.github.novacrypto.bip39.SeedCalculator; import io.github.novacrypto.bip39.Words; import io.github.novacrypto.bip39.wordlists.English; import io.github.novacrypto.hashing.Sha256; import lombok.extern.slf4j.Slf4j; import org.apache.commons.lang3.StringUtils; import org.apache.http.HttpResponse; import org.apache.http.util.EntityUtils; import org.springframework.stereotype.Service; import org.web3j.abi.FunctionEncoder; import org.web3j.abi.datatypes.Address; import org.web3j.abi.datatypes.Function; import org.web3j.abi.datatypes.generated.Uint256; import org.web3j.crypto.*; import org.web3j.utils.Convert; import org.web3j.utils.Numeric; import javax.annotation.Resource; import java.math.BigInteger; import java.security.SecureRandom; import java.util.*; @Slf4j @Service public class EAccountServiceImpl implements IAccountService {@Resource private IRedisService redisService; private final Map, String> headers = new HashMap<>(); private final Map, String> querys = headers; @Override public JSONObject createAccount(String pwd) {StringBuilder sb = new StringBuilder(); byte[] entropy = new byte[Words.TWELVE.byteLength()]; new SecureRandom().nextBytes(entropy); new MnemonicGenerator(English.INSTANCE).createMnemonic(entropy, sb::append); String mnemonic = sb.toString(); List mnemonicList = Arrays.asList(mnemonic.split(" ")); byte[] seed = new SeedCalculator().withWordsFromWordList(English.INSTANCE).calculateSeed(mnemonicList, pwd); ECKeyPair ecKeyPair = ECKeyPair.create(Sha256.sha256(seed)); String privateKey = ecKeyPair.getPrivateKey().toString(16); String publicKey = ecKeyPair.getPublicKey().toString(16); String address = "0x" + Keys.getAddress(publicKey); JSONObject json = new JSONObject(); json.put("privateKey", privateKey); json.put("publicKey", publicKey); json.put("address", address); return json; }@Override public JSONObject getGasPrice() throws Exception {StringBuffer path = new StringBuffer("/api?module=gastracker&action=gasoracle&apikey=").append(EthConstant.ETHERSCAN_API_KEY); HttpResponse response = HttpUtils.doGet("https://api.etherscan.io", path.toString(), "GET", headers, querys); String res = EntityUtils.toString(response.getEntity()); JSONObject json = JSONObject.parseObject(res); String status = json.getString("status"); if(!status.equals("1")){ throw new Exception(json.getString("message")); } JSONObject resJson = json.getJSONObject("result"); return resJson; }@Override public String checkTran(String hash) throws Exception {StringBuffer path = new StringBuffer("/api?module=transaction&action=getstatus&txhash=").append(hash) .append("&apikey=").append(EthConstant.ETHERSCAN_API_KEY); HttpResponse response = HttpUtils.doGet("https://api.etherscan.io", path.toString(), "GET", headers, querys); String res = EntityUtils.toString(response.getEntity()); JSONObject json = JSONObject.parseObject(res); String status = json.getString("status"); if(!status.equals("1")){ throw new Exception(json.getString("message")); } JSONObject resJson = json.getJSONObject("result"); return resJson.getString("isError"); }@Override public String checkTranPending(String hash) throws Exception {StringBuffer path = new StringBuffer("/api?module=transaction&action=gettxreceiptstatus&txhash=").append(hash) .append("&apikey=").append(EthConstant.ETHERSCAN_API_KEY); HttpResponse response = HttpUtils.doGet("https://api.etherscan.io", path.toString(), "GET", headers, querys); String res = EntityUtils.toString(response.getEntity()); JSONObject json = JSONObject.parseObject(res); String status = json.getString("status"); if(!status.equals("1")){ throw new Exception(json.getString("message")); } JSONObject resJson = json.getJSONObject("result"); return resJson.getString("status"); }@Override public BigInteger getTranNum(String address) throws Exception { //注意这里api上是tag=lasted 是查不到pending中的交易的 StringBuffer path = new StringBuffer("/api?module=proxy&action=eth_getTransactionCount&address=").append(address) .append("&tag=pending&apikey=").append(EthConstant.ETHERSCAN_API_KEY); HttpResponse response = HttpUtils.doGet("https://api.etherscan.io", path.toString(), "GET", headers, querys); String res = EntityUtils.toString(response.getEntity()); JSONObject json = JSONObject.parseObject(res); String result = json.getString("result"); return new BigInteger(result.substring(2), 16); }@Override public String getEthBalance(String address) throws Exception {StringBuffer path = new StringBuffer("/api?module=account&action=balance&address=").append(address) .append("&tag=latest&apikey=").append(EthConstant.ETHERSCAN_API_KEY); HttpResponse response = HttpUtils.doGet("https://api.etherscan.io", path.toString(), "GET", headers, querys); String res = EntityUtils.toString(response.getEntity()); JSONObject json = JSONObject.parseObject(res); String status = json.getString("status"); if(!status.equals("1")){ throw new Exception(json.getString("message")); } String num = json.getString("result"); return Convert.fromWei(num, Convert.Unit.ETHER).toString(); }@Override public String getUsdtBalance(String address) throws Exception { StringBuffer path = new StringBuffer("/api?module=account&action=tokenbalance&contractaddress=").append(EthConstant.CONTRACTA_DDRESS) .append("&address=").append(address).append("&tag=latest&apikey=").append(EthConstant.ETHERSCAN_API_KEY); HttpResponse response = HttpUtils.doGet("https://api.etherscan.io", path.toString(), "GET", headers, querys); String res = EntityUtils.toString(response.getEntity()); JSONObject json = JSONObject.parseObject(res); String status = json.getString("status"); if(!status.equals("1")){ throw new Exception(json.getString("message")); } String num = json.getString("result"); return Convert.fromWei(num, Convert.Unit.MWEI).toString(); }@Override public JSONObject tranEth(String from, String to, String privateKey, String num, String gasPrice, String nonce) throws Exception {BigInteger gasPriceNum = null; if(StringUtils.isNotBlank(gasPrice) && new BigInteger(gasPrice).compareTo(new BigInteger("1")) >= 0){ gasPriceNum = Convert.toWei(gasPrice, Convert.Unit.GWEI).toBigInteger(); } else { gasPriceNum = Convert.toWei(getGasPrice().getString("ProposeGasPrice"), Convert.Unit.GWEI).toBigInteger(); } BigInteger nonceMum = null; if(StringUtils.isNotBlank(nonce) && new BigInteger(nonce).compareTo(new BigInteger("0")) >= 0){ nonceMum = new BigInteger(nonce); } else { nonceMum = this.getTranNum(from); } RawTransaction rawTransaction = RawTransaction.createEtherTransaction( nonceMum, gasPriceNum , new BigInteger("21000"), to,Convert.toWei(num, Convert.Unit.ETHER).toBigInteger()); Credentials credentials = Credentials.create(privateKey); byte[] signedMessage = TransactionEncoder.signMessage(rawTransaction, credentials); String hexValue = https://www.it610.com/article/Numeric.toHexString(signedMessage); StringBuffer path = new StringBuffer("/api?module=proxy&action=eth_sendRawTransaction&hex=").append(hexValue) .append("&apikey=").append(EthConstant.ETHERSCAN_API_KEY); HttpResponse response = HttpUtils.doGet("https://api.etherscan.io", path.toString(), "GET", headers, querys); String res = EntityUtils.toString(response.getEntity()); JSONObject json = JSONObject.parseObject(res); log.info(json.toString()); String hash = json.getString("result"); if(StringUtils.isBlank(hash)){ throw new Exception(json.getJSONObject("error").getString("message")); }JSONObject jsonObject = new JSONObject(); jsonObject.put("nonce", nonce); jsonObject.put("hash", hash); return jsonObject; }@Override public JSONObject tranUsdt(String from, String to, String privateKey, String num , String gasPrice, String gaslimit, String nonce) throws Exception {BigInteger tranNum = Convert.toWei(num, Convert.Unit.MWEI).toBigInteger(); Function function = new Function("transfer", Arrays.asList( new Address(to), new Uint256(tranNum) ), Collections.emptyList()); String encodeFunction = FunctionEncoder.encode(function); BigInteger gasPriceNum = null; if(StringUtils.isNotBlank(gasPrice) && new BigInteger(gasPrice).compareTo(new BigInteger("1")) >= 0){ gasPriceNum = Convert.toWei(gasPrice, Convert.Unit.GWEI).toBigInteger(); } else { gasPriceNum = Convert.toWei(getGasPrice().getString("ProposeGasPrice"), Convert.Unit.GWEI).toBigInteger(); } BigInteger gasLimitNum = new BigInteger("100000"); if(StringUtils.isNotBlank(gaslimit) && new BigInteger(gaslimit).compareTo(new BigInteger("21000")) >= 0){ gasLimitNum = new BigInteger(gaslimit); } BigInteger nonceMum = null; if(StringUtils.isNotBlank(nonce) && new BigInteger(nonce).compareTo(new BigInteger("0")) >= 0){ nonceMum = new BigInteger(nonce); } else { nonceMum = this.getTranNum(from); } RawTransaction rawTransaction = RawTransaction.createTransaction( nonceMum, gasPriceNum, gasLimitNum , EthConstant.CONTRACTA_DDRESS, encodeFunction); Credentials credentials = Credentials.create(privateKey); byte[] signedMessage = TransactionEncoder.signMessage(rawTransaction, credentials); String hexValue = https://www.it610.com/article/Numeric.toHexString(signedMessage); StringBuffer path = new StringBuffer("/api?module=proxy&action=eth_sendRawTransaction&hex=").append(hexValue) .append("&apikey=").append(EthConstant.ETHERSCAN_API_KEY); HttpResponse response = HttpUtils.doGet("https://api.etherscan.io", path.toString(), "GET", headers, querys); String res = EntityUtils.toString(response.getEntity()); JSONObject json = JSONObject.parseObject(res); log.info(json.toString()); String hash = json.getString("result"); if(StringUtils.isBlank(hash)){ throw new Exception(json.getJSONObject("error").getString("message")); }JSONObject jsonObject = new JSONObject(); jsonObject.put("nonce", nonceMum); jsonObject.put("hash", hash); return jsonObject; } }

http工具类

package com.lim.util; import org.apache.commons.lang3.StringUtils; import org.apache.http.HttpResponse; import org.apache.http.NameValuePair; import org.apache.http.client.HttpClient; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.conn.ClientConnectionManager; import org.apache.http.conn.scheme.Scheme; import org.apache.http.conn.scheme.SchemeRegistry; import org.apache.http.conn.ssl.SSLSocketFactory; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import javax.net.ssl.SSLContext; import javax.net.ssl.TrustManager; import javax.net.ssl.X509TrustManager; import java.io.UnsupportedEncodingException; import java.net.URLEncoder; import java.security.KeyManagementException; import java.security.NoSuchAlgorithmException; import java.security.cert.X509Certificate; import java.util.ArrayList; import java.util.List; import java.util.Map; public class HttpUtils { public static HttpResponse doGet(String host, String path, String method, Map, String> headers, Map, String> querys) throws Exception { HttpClient httpClient = wrapClient(host); HttpGet request = new HttpGet(buildUrl(host, path, querys)); for (Map.Entry, String> e : headers.entrySet()) { request.addHeader(e.getKey(), e.getValue()); }return httpClient.execute(request); } public static HttpResponse doPost(String host, String path, String method, Map, String> headers, Map, String> querys, Map, String> bodys) throws Exception { HttpClient httpClient = wrapClient(host); HttpPost request = new HttpPost(buildUrl(host, path, querys)); for (Map.Entry, String> e : headers.entrySet()) { request.addHeader(e.getKey(), e.getValue()); }if (bodys != null) { List nameValuePairList = new ArrayList(); for (String key : bodys.keySet()) { nameValuePairList.add(new BasicNameValuePair(key, bodys.get(key))); } UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(nameValuePairList, "utf-8"); formEntity.setContentType("application/x-www-form-urlencoded; charset=UTF-8"); request.setEntity(formEntity); }return httpClient.execute(request); } private static String buildUrl(String host, String path, Map, String> querys) throws UnsupportedEncodingException { StringBuilder sbUrl = new StringBuilder(); sbUrl.append(host); if (!StringUtils.isBlank(path)) { sbUrl.append(path); } if (null != querys) { StringBuilder sbQuery = new StringBuilder(); for (Map.Entry, String> query : querys.entrySet()) { if (0 < sbQuery.length()) { sbQuery.append("&"); } if (StringUtils.isBlank(query.getKey()) && !StringUtils.isBlank(query.getValue())) { sbQuery.append(query.getValue()); } if (!StringUtils.isBlank(query.getKey())) { sbQuery.append(query.getKey()); if (!StringUtils.isBlank(query.getValue())) { sbQuery.append("="); sbQuery.append(URLEncoder.encode(query.getValue(), "utf-8")); } } } if (0 < sbQuery.length()) { sbUrl.append("?").append(sbQuery); } }return sbUrl.toString(); } private static HttpClient wrapClient(String host) { HttpClient httpClient = new DefaultHttpClient(); if (host.startsWith("https://")) { sslClient(httpClient); }return httpClient; } private static void sslClient(HttpClient httpClient) { try { SSLContext ctx = SSLContext.getInstance("TLS"); X509TrustManager tm = new X509TrustManager() { public X509Certificate[] getAcceptedIssuers() { return null; } public void checkClientTrusted(X509Certificate[] xcs, String str) {} public void checkServerTrusted(X509Certificate[] xcs, String str) {} }; ctx.init(null, new TrustManager[] { tm }, null); SSLSocketFactory ssf = new SSLSocketFactory(ctx); ssf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER); ClientConnectionManager ccm = httpClient.getConnectionManager(); SchemeRegistry registry = ccm.getSchemeRegistry(); registry.register(new Scheme("https", 443, ssf)); } catch (KeyManagementException ex) { throw new RuntimeException(ex); } catch (NoSuchAlgorithmException ex) { throw new RuntimeException(ex); } } }

【web3j|java开发以太坊---不搭节点开发】常量类

package com.lim.eth; public class EthConstant {//redis key 存储账户地址的pending交易集用于计算nonce public static final String ADDRESS_TRAN_PENDING_KEY = "address.tran.pending.key-"; //etherscan api秘钥 public static final String ETHERSCAN_API_KEY = "******自己申请的秘钥******"; //ERC20_USDT合约地址 public static final String CONTRACTA_DDRESS = "0xdac17f958d2ee523a2206206994597c13d831ec7"; }