web3j:智能合约写操作时总是抛出java.lang.ArrayIndexOutOfBoundsException错误，不知道什么问题。
我的代码如下：
String hexPrivateKey = String.format("%040x", new BigInteger(1, Config.privateKey.getBytes()));
String hexPublicKey = String.format("%040x", new BigInteger(1, Config.publicKey.getBytes()));
Credentials credentials = Credentials.create(hexPrivateKey, hexPublicKey);
DataSaver contract = DataSaver.load(
address, web3j, credentials, Contract.GAS_PRICE, Contract.GAS_LIMIT);
RemoteCall transaction2 = contract.updateDocumentPayload(
BigInteger.valueOf(1), "Test");
transaction2.send();
读取操作是成功的。写入返回以下错误：
java.lang.ArrayIndexOutOfBoundsException
at java.lang.System.arraycopy(Native Method)
at org.bouncycastle.crypto.signers.HMacDSAKCalculator.init(Unknown Source)
at org.bouncycastle.crypto.signers.ECDSASigner.generateSignature(Unknown Source)
at org.web3j.crypto.ECKeyPair.sign(ECKeyPair.java:46)
at org.web3j.crypto.Sign.signMessage(Sign.java:52)
at org.web3j.crypto.Sign.signMessage(Sign.java:40)
at org.web3j.crypto.TransactionEncoder.signMessage(TransactionEncoder.java:21)
at org.web3j.tx.RawTransactionManager.signAndSend(RawTransactionManager.java:102)
at org.web3j.tx.RawTransactionManager.sendTransaction(RawTransactionManager.java:91)
at org.web3j.tx.TransactionManager.executeTransaction(TransactionManager.java:49)
at org.web3j.tx.ManagedTransaction.send(ManagedTransaction.java:83)
at org.web3j.tx.Contract.executeTransaction(Contract.java:242)
at org.web3j.tx.Contract.executeTransaction(Contract.java:226)
at org.web3j.tx.Contract.executeTransaction(Contract.java:220)
at org.web3j.tx.Contract.lambda$executeRemoteCallTransaction$3(Contract.java:259)
at org.web3j.protocol.core.RemoteCall.send(RemoteCall.java:30)
at com.company.api.v1.contract.ContractDocumentPayload.postDocumentPayload(ContractDocumentPayload.java:104)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory$1.invoke(ResourceMethodInvocationHandlerFactory.java:81)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:144)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:161)
at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:205)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:99)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:389)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:347)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:102)
at org.glassfish.jersey.server.ServerRuntime$2.run(ServerRuntime.java:326)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:317)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:305)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1154)
at org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:473)
at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:427)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:388)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:341)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:228)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:651)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:409)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:754)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1376)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
问题的解决
应该是将错误的私钥传递给webb3j来签署交易时，会将引发该异常。请看下面的例子。
正确的工作代码（带有有效私钥）：
BigInteger privateKey = new BigInteger("f9c8a5d689736d881cf9b4117bbae6d935b2368f8260a25677e35d4d1eea7231", 16);
BigInteger publicKey = new BigInteger("72445fcfdeb1fff79496d7ce66089d663ff90e26", 16);
ECKeyPair pair = new ECKeyPair(privateKey, publicKey);
pair.sign("".getBytes());
相同的代码使用无效的私钥（随便添加一个数字比如a），就会抛出与你完全相同的异常：
BigInteger privateKey = new BigInteger("f9c8a5d689736d881cf9b4117bbae6d935b2368f8260a25677e35d4d1eea7231a", 16);
BigInteger publicKey = new BigInteger("72445fcfdeb1fff79496d7ce66089d663ff90e26a", 16);
ECKeyPair pair = new ECKeyPair(privateKey, publicKey);
pair.sign("".getBytes());
始终通过WalletUtils.isValidPrivateKey()和WalletUtils.isValidAddress()来检查私钥和地址是否有效。