fabric-sdk-java for Service Discovery

前言

在fabric区块链网络下，fabric-sdk-java开发的application主要与peer节点交互，通过peer节点提交proposal request，完成背书之后提交到orderer节点进行排序打包。
在此过程中，若peer节点出现故障，就会导致proposal request提交失败，进而造成application不可用。因此，在fabric 1.2版本中提出了 Service Discovery来解决peer节点高可用的问题。

Service Discovery for fabric-sdk-java

以下demo使用fabric-sdk-java服务发现API实现查询和提交交易
此demo使用fabric-java-sd依赖版本为 1.4.8。

<!-- https://mvnrepository.com/artifact/org.hyperledger.fabric-sdk-java/fabric-sdk-java -->     <dependency>       <groupId>org.hyperledger.fabric-sdk-java</groupId>       <artifactId>fabric-sdk-java</artifactId>       <version>1.4.8</version>     </dependency> 

采用单机部署的raft共识的fabric区块链网络，5个orderer节点，4个peer节点，fabric版本为1.4.6
代码后面有相关的注意事项，有兴趣的朋友建议看到最后。
本demo采用的fabric网络实例地址：https://download.csdn.net/download/weixin_43562234/12442601

代码

TestServiceDiscovery.class

package com.richfit.fabric.serviceDiscovery;  import com.richfit.fabric.serviceDiscovery.configure.Configurations; import org.hyperledger.fabric.sdk.*; import org.hyperledger.fabric.sdk.security.CryptoSuite;  import java.io.File; import java.nio.file.Files; import java.nio.file.Paths; import java.util.*; import java.util.concurrent.TimeUnit;  public class TestServiceDiscovery {     private static final long waitTime = 10000;       public static void main(String[] args) throws Exception {         //Configurations configurations = new Configurations();             HFClient client = HFClient.createNewInstance();          String userName = "Admin@org1.example.com";         String mspId = "Org1MSP";         String chaincodeName = "mycc";          String keyDir = "src/main/java/com/richfit/fabric/serviceDiscovery/configure/crypto-config/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp/keystore";         String keyFile = getKeyFilesInDir(new File(keyDir)).toString();         String certFile = "src/main/java/com/richfit/fabric/serviceDiscovery/configure/crypto-config/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp/signcerts/Admin@org1.example.com-cert.pem";           //create user object         FabricUser user = new FabricUser(userName, mspId, keyFile, certFile);          //encryption suite         client.setCryptoSuite(CryptoSuite.Factory.getCryptoSuite());         client.setUserContext(user);          String channelName = "mychannel";          //create channel object         Channel channel = client.newChannel(channelName);          //create peer0org1         String peer0org1TLSCert = "src/main/java/com/richfit/fabric/serviceDiscovery/configure/crypto-config/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt";         Properties peer0org1_properties = new Properties();         peer0org1_properties.put("pemBytes", Files.readAllBytes(Paths.get(peer0org1TLSCert)));         peer0org1_properties.setProperty("sslProvider", "openSSL");         peer0org1_properties.setProperty("negotiationType", "TLS");         peer0org1_properties.setProperty("trustServerCertificate", "true");         String peer0org1Name = "peer0.org1.example.com";         String peer0org1URL = "grpcs://peer0.org1.example.com:7051";         peer0org1_properties.setProperty("hostnameOverride", peer0org1Name);          Peer peer0org1 = client.newPeer(peer0org1Name, peer0org1URL, peer0org1_properties);          //create peer1org1         String peer1org1TLSCert = "src/main/java/com/richfit/fabric/serviceDiscovery/configure/crypto-config/peerOrganizations/org1.example.com/peers/peer1.org1.example.com/tls/ca.crt";         Properties peer1org1_properties = new Properties();         peer1org1_properties.put("pemBytes", Files.readAllBytes(Paths.get(peer1org1TLSCert)));         peer1org1_properties.setProperty("sslProvider", "openSSL");         peer1org1_properties.setProperty("negotiationType", "TLS");         peer1org1_properties.setProperty("trustServerCertificate", "true");         String peer1org1Name = "peer1.org1.example.com";         String peer1org1URL = "grpcs://peer1.org1.example.com:8051";         peer1org1_properties.setProperty("hostnameOverride", peer1org1Name);          Peer peer1org1 = client.newPeer(peer1org1Name, peer1org1URL, peer1org1_properties);          //create peer0org2         String peer0org2TLSCert = "src/main/java/com/richfit/fabric/serviceDiscovery/configure/crypto-config/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt";         Properties peer0org2_properties = new Properties();         peer0org2_properties.put("pemBytes", Files.readAllBytes(Paths.get(peer0org2TLSCert)));         peer0org2_properties.setProperty("sslProvider", "openSSL");         peer0org2_properties.setProperty("negotiationType", "TLS");         peer0org2_properties.setProperty("trustServerCertificate", "true");         String peer0org2Name = "peer0.org2.example.com";         String peer0org2URL = "grpcs://peer0.org2.example.com:9051";         peer0org2_properties.setProperty("hostnameOverride", peer0org2Name);         Peer peer0org2 = client.newPeer(peer0org2Name, peer0org2URL, peer0org2_properties);          //create peer1org2         String peer1org2TLSCert = "src/main/java/com/richfit/fabric/serviceDiscovery/configure/crypto-config/peerOrganizations/org2.example.com/peers/peer1.org2.example.com/tls/ca.crt";         Properties peer1org2_properties = new Properties();         peer1org2_properties.put("pemBytes", Files.readAllBytes(Paths.get(peer1org2TLSCert)));         peer1org2_properties.setProperty("sslProvider", "openSSL");         peer1org2_properties.setProperty("negotiationType", "TLS");         peer1org2_properties.setProperty("trustServerCertificate", "true");         String peer1org2Name = "peer1.org2.example.com";         String peer1org2URL = "grpcs://peer1.org2.example.com:10051";         peer1org2_properties.setProperty("hostnameOverride", peer1org2Name);         Peer peer1org2 = client.newPeer(peer1org2Name, peer1org2URL, peer1org2_properties);           channel.addPeer(peer0org1, Channel.PeerOptions.createPeerOptions().setPeerRoles(EnumSet.of(Peer.PeerRole.SERVICE_DISCOVERY, Peer.PeerRole.LEDGER_QUERY, Peer.PeerRole.EVENT_SOURCE, Peer.PeerRole.CHAINCODE_QUERY)));         channel.addPeer(peer1org1, Channel.PeerOptions.createPeerOptions().setPeerRoles(EnumSet.of(Peer.PeerRole.SERVICE_DISCOVERY, Peer.PeerRole.LEDGER_QUERY, Peer.PeerRole.EVENT_SOURCE, Peer.PeerRole.CHAINCODE_QUERY)));         channel.addPeer(peer0org2, Channel.PeerOptions.createPeerOptions().setPeerRoles(EnumSet.of(Peer.PeerRole.SERVICE_DISCOVERY, Peer.PeerRole.LEDGER_QUERY, Peer.PeerRole.EVENT_SOURCE, Peer.PeerRole.CHAINCODE_QUERY)));         channel.addPeer(peer1org2, Channel.PeerOptions.createPeerOptions().setPeerRoles(EnumSet.of(Peer.PeerRole.SERVICE_DISCOVERY, Peer.PeerRole.LEDGER_QUERY, Peer.PeerRole.EVENT_SOURCE, Peer.PeerRole.CHAINCODE_QUERY)));            //init channel         channel.initialize();          //queryByChaincode(client, chaincodeName, channel);         insertByChaincode(client,chaincodeName,channel);     }      public static void queryByChaincode(HFClient client, String chaincodeName , Channel channel) throws Exception {                 ChaincodeID chaincodeID = ChaincodeID.newBuilder().setName(chaincodeName).build();          //build args         ArrayList<String> argsList = new ArrayList<>();         argsList.add("a");         String function = "query";         executeTransaction(client, channel, chaincodeID,false, function, argsList);     }      public static void insertByChaincode(HFClient client, String chaincodeName , Channel channel) throws Exception {         ChaincodeID chaincodeID = ChaincodeID.newBuilder().setName(chaincodeName).build();          ArrayList<String> argsList = new ArrayList<>();         argsList.add("b");         argsList.add("a");         argsList.add("10");          String function = "invoke";         executeTransaction(client, channel, chaincodeID,true ,function, argsList);      }      private static void executeTransaction(HFClient client, Channel channel, ChaincodeID chaincodeID, boolean invoke, String func, ArrayList<String> args) throws Exception {         TransactionProposalRequest transactionProposalRequest = client.newTransactionProposalRequest();         transactionProposalRequest.setChaincodeID(chaincodeID);         transactionProposalRequest.setChaincodeLanguage(TransactionRequest.Type.JAVA);          transactionProposalRequest.setFcn(func);         transactionProposalRequest.setArgs(args);         transactionProposalRequest.setProposalWaitTime(waitTime);         List<ProposalResponse> successful = new LinkedList<ProposalResponse>();         List<ProposalResponse> failed = new LinkedList<ProposalResponse>();         // java sdk         // 通常会发送交易请求给所有peer节点，如果有一些peer节点宕机，但是有Response到达了背书节点的话，我们可以不选择重新发送交易请求，使用服务发现功能可以实现这一目标。         Collection<ProposalResponse> transactionPropResp;         // 确保配置有服务发现功能的peer节点数量大于0         if (channel.getPeers(EnumSet.of(Peer.PeerRole.SERVICE_DISCOVERY)).size() > 0) {             System.out.println("配置有服务发现功能的peer节点数量：" + channel.getPeers(EnumSet.of(Peer.PeerRole.SERVICE_DISCOVERY)).size());             // 配置服务发现在fabric网络中，使用服务发现来寻找背书节点（endorsing peers）             Channel.DiscoveryOptions discoveryOptions = Channel.DiscoveryOptions.createDiscoveryOptions();             // 随机选取满足背书策略的peer节点组合 ENDORSEMENT_SELECTION_RANDOM             // 选取满足背书策略的，状态最新、块高最大的peer节点组合 ENDORSEMENT_SELECTION_LEAST_REQUIRED_BLOCKHEIGHT             discoveryOptions.setEndorsementSelector(ServiceDiscovery.EndorsementSelector.ENDORSEMENT_SELECTION_RANDOM);             // discoveryOptions.setEndorsementSelector(ServiceDiscovery.EndorsementSelector.ENDORSEMENT_SELECTION_LEAST_REQUIRED_BLOCKHEIGHT);             // setForceDiscovery true :每一次发送proposal时都调用discovery服务获取peer列表，会有一定的资源消耗             // setForceDiscovery false :发送proposal时使用discovery服务缓存的peer列表，默认2分钟刷新一次             discoveryOptions.setForceDiscovery(false);             // setInspectResults true: 关闭SDK 背书策略检查，由应用逻辑进行判断             // false:SDK 自动进行背书策略检查，不满足抛出异常             discoveryOptions.setInspectResults(true);             transactionPropResp = channel.sendTransactionProposalToEndorsers(transactionProposalRequest, discoveryOptions);         } else {             System.out.println("peers:" + channel.getPeers(EnumSet.of(Peer.PeerRole.SERVICE_DISCOVERY)).size());             transactionPropResp = channel.sendTransactionProposal(transactionProposalRequest, channel.getPeers(EnumSet.of(Peer.PeerRole.ENDORSING_PEER)));         }          for (ProposalResponse response : transactionPropResp) {             System.out.println("ChaincodeActionResponseStatus:"+response.getChaincodeActionResponseStatus());             System.out.println("ChaincodeActionResponsePayload:"+ Arrays.toString(response.getChaincodeActionResponsePayload()));             System.out.println(""+response.getProposalResponse());             //System.out.println();             if (response.getStatus() == ProposalResponse.Status.SUCCESS) {                 String payload = response.getProposalResponse().getResponse().getPayload().toStringUtf8();                 if (payload.isEmpty()) {                     System.out.println("******************************************************************************");                     System.out.println(String.format("[√] 得到成功响应从 peer %s", response.getPeer().getName()));                 } else {                     System.out.println("******************************************************************************");                     System.out.println(                             String.format("[√] 得到成功响应从 peer %s => payload: %s", response.getPeer().getName(), payload));                 }                 successful.add(response);             } else {                 String status = response.getStatus().toString();                 String msg = response.getMessage();                 System.out.println(String.format("[×] 响应失败从 peer %s => %s: %s ", response.getPeer().getName(), status, msg));                 failed.add(response);             }         }          if (invoke) {             Channel.TransactionOptions opts = new Channel.TransactionOptions();             Channel.NOfEvents nOfEvents = Channel.NOfEvents.createNofEvents();             nOfEvents.addPeers(channel.getPeers(EnumSet.of(Peer.PeerRole.EVENT_SOURCE)));             nOfEvents.setN(1);             opts.nOfEvents(nOfEvents);             System.out.println("向orderers发送交易...");             channel.sendTransaction(successful, opts).thenApply(transactionEvent -> {                 System.out.println("Orderer 响应: txid" + transactionEvent.getTransactionID());                 System.out.println("Orderer 响应: 区块编号: " + transactionEvent.getBlockEvent().getBlockNumber());                 return null;             }).exceptionally(e -> {                 System.out.println("Orderer exception happened: "+ e);                 return null;             }).get(waitTime, TimeUnit.SECONDS);         }      }      private static File getKeyFilesInDir(File filePath) {         File keyFile = null;         File[] listFiles = filePath.listFiles();         if (listFiles != null) {             for (File file : listFiles) {                 if (file.isFile()) {                     if (file.getName().endsWith("_sk")) {                         keyFile = file;                         break;                     }                 }             }         }         return keyFile;     }  }  

FabricUser.class

package com.richfit.fabric.serviceDiscovery;  import org.hyperledger.fabric.sdk.Enrollment; import org.hyperledger.fabric.sdk.User; import org.hyperledger.fabric.sdk.identity.X509Enrollment; import org.hyperledger.fabric.sdk.security.CryptoPrimitives;  import java.nio.file.Files; import java.nio.file.Paths; import java.security.PrivateKey; import java.util.Set;   /**  * @author adder  * @date 2020/1/20 15:43  */ public class FabricUser implements User {     private String name;     private String mspId;     private Enrollment enrollment;     private String keyFile;     private String certFile;      public FabricUser(String name, String mspId, String keyFile, String certFile) {         this.name = name;         this.mspId = mspId;         this.keyFile=keyFile;         this.certFile=certFile;          try{             enrollment=loadFromPemFile(keyFile, certFile);         }catch(Exception ex){             ex.printStackTrace();         }     }      private Enrollment loadFromPemFile(String keyFile,String certFile) throws Exception{         byte[] keyPem = Files.readAllBytes(Paths.get(keyFile));     //load private key text         byte[] certPem = Files.readAllBytes(Paths.get(certFile));   //load certificate text         CryptoPrimitives suite = new CryptoPrimitives();            //load the cryptography suite         PrivateKey privateKey = suite.bytesToPrivateKey(keyPem);    //convert private key text to object         return new X509Enrollment(privateKey,new String(certPem));  //create X509Enrollment object     }      @Override     public String getName() {         return name;     }      @Override     public String getMspId() {         return mspId;     }      @Override     public Enrollment getEnrollment() {         return enrollment;     }      @Override     public String getAccount() {         return null;     }      @Override     public String getAffiliation() {         return null;     }      @Override     public Set<String> getRoles() {         return null;     }      public String getKeyFile() {         return keyFile;     }      public void setKeyFile(String keyFile) {         this.keyFile = keyFile;     }      public String getCertFile() {         return certFile;     }      public void setCertFile(String certFile) {         this.certFile = certFile;     }  }  

注意！！！

1. 服务发现主要依赖于GOSSIP协议，通过在peer节点的配置文件中添加CORE_PEER_GOSSIP_EXTERNALENDPOINT=peer1.org1.example.com:8051配置，来实现peer节点主动向channel中广播自己的状态。
2. orderer节点本身会向channel广播自身的状态，因此不需要修改orderer节点的配置文件，在开发application时调用java sdk的服务发现的API也不需要向channel中add orderer节点（没有使用服务发现的时候是需要在channel中添加orderer的）。
3. orderer节点通过grpc服务与外部通讯，其grpc服务端口默认的是7050。需要注意的是，在单台服务器上部署多个orderer节点的时候，需要修改ORDERER_GENERAL_LISTENPORT=7050环境变量的端口号，使其与orderer节点在服务器上对外暴露的端口保持一致，否则在使用sdk调用服务发现API的时候会出现异常，异常信息如下：

19:10:04.242 [main] DEBUG org.hyperledger.fabric.sdk.Orderer - Orderer.sendTransaction Orderer{id: 18, channelName: mychannel, name:orderer4.example.com:7050, url: grpcs://orderer4.example.com:7050} 19:10:04.244 [main] DEBUG org.hyperledger.fabric.sdk.Endpoint - Endpoint grpcs://orderer4.example.com:7050 with no ssl context 19:10:04.254 [grpc-default-worker-ELG-1-16] DEBUG io.netty.handler.ssl.ReferenceCountedOpenSslContext - verification of certificate failed java.security.cert.CertificateException: No subject alternative DNS name matching orderer4.example.com found.  at sun.security.util.HostnameChecker.matchDNS(HostnameChecker.java:214)  at sun.security.util.HostnameChecker.match(HostnameChecker.java:96)  at sun.security.ssl.X509TrustManagerImpl.checkIdentity(X509TrustManagerImpl.java:455)  at sun.security.ssl.X509TrustManagerImpl.checkIdentity(X509TrustManagerImpl.java:436)  at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:252)  at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:136)  at io.netty.handler.ssl.OpenSslTlsv13X509ExtendedTrustManager.checkServerTrusted(OpenSslTlsv13X509ExtendedTrustManager.java:223)  at io.netty.handler.ssl.ReferenceCountedOpenSslClientContext$ExtendedTrustManagerVerifyCallback.verify(ReferenceCountedOpenSslClientContext.java:255)  at io.netty.handler.ssl.ReferenceCountedOpenSslContext$AbstractCertificateVerifier.verify(ReferenceCountedOpenSslContext.java:701)  at io.netty.internal.tcnative.SSL.readFromSSL(Native Method)  at io.netty.handler.ssl.ReferenceCountedOpenSslEngine.readPlaintextData(ReferenceCountedOpenSslEngine.java:593)  at io.netty.handler.ssl.ReferenceCountedOpenSslEngine.unwrap(ReferenceCountedOpenSslEngine.java:1176)  at io.netty.handler.ssl.ReferenceCountedOpenSslEngine.unwrap(ReferenceCountedOpenSslEngine.java:1293)  at io.netty.handler.ssl.ReferenceCountedOpenSslEngine.unwrap(ReferenceCountedOpenSslEngine.java:1336)  at io.netty.handler.ssl.SslHandler$SslEngineType$1.unwrap(SslHandler.java:204)  at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1332)  at io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1227)  at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1274)  at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:503)  at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:442)  at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:281)  at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)  at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)  at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)  at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1422)  at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)  at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)  at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:931)  at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)  at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:700)  at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:635)  at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:552)  at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:514)  at io.netty.util.concurrent.SingleThreadEventExecutor$6.run(SingleThreadEventExecutor.java:1050)  at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)  at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)  at java.lang.Thread.run(Thread.java:748) 19:10:04.259 [grpc-default-executor-1] ERROR org.hyperledger.fabric.sdk.OrdererClient - OrdererClient{id: 23, channel: mychannel, name: orderer4.example.com:7050, url: grpcs://orderer4.example.com:7050}  managed channel isTerminated: false, isShutdown: false, state: TRANSIENT_FAILURE 19:10:04.259 [grpc-default-executor-1] ERROR org.hyperledger.fabric.sdk.OrdererClient - Received error org.hyperledger.fabric.sdk.OrdererClient$1@6e8ba5db  UNAVAILABLE: io exception io.grpc.StatusRuntimeException: UNAVAILABLE: io exception  at io.grpc.Status.asRuntimeException(Status.java:530)  at io.grpc.stub.ClientCalls$StreamObserverToCallListenerAdapter.onClose(ClientCalls.java:434)  at io.grpc.PartialForwardingClientCallListener.onClose(PartialForwardingClientCallListener.java:39)  at io.grpc.ForwardingClientCallListener.onClose(ForwardingClientCallListener.java:23)  at io.grpc.ForwardingClientCallListener$SimpleForwardingClientCallListener.onClose(ForwardingClientCallListener.java:40)  at io.grpc.internal.CensusStatsModule$StatsClientInterceptor$1$1.onClose(CensusStatsModule.java:694)  at io.grpc.PartialForwardingClientCallListener.onClose(PartialForwardingClientCallListener.java:39)  at io.grpc.ForwardingClientCallListener.onClose(ForwardingClientCallListener.java:23)  at io.grpc.ForwardingClientCallListener$SimpleForwardingClientCallListener.onClose(ForwardingClientCallListener.java:40)  at io.grpc.internal.CensusTracingModule$TracingClientInterceptor$1$1.onClose(CensusTracingModule.java:397)  at io.grpc.internal.ClientCallImpl.closeObserver(ClientCallImpl.java:459)  at io.grpc.internal.ClientCallImpl.access$300(ClientCallImpl.java:63)  at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl.close(ClientCallImpl.java:546)  at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl.access$600(ClientCallImpl.java:467)  at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInContext(ClientCallImpl.java:584)  at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)  at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:123)  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)  at java.lang.Thread.run(Thread.java:748) Caused by: javax.net.ssl.SSLHandshakeException: General OpenSslEngine problem  at io.netty.handler.ssl.ReferenceCountedOpenSslEngine.handshakeException(ReferenceCountedOpenSslEngine.java:1732)  at io.netty.handler.ssl.ReferenceCountedOpenSslEngine.wrap(ReferenceCountedOpenSslEngine.java:774)  at javax.net.ssl.SSLEngine.wrap(SSLEngine.java:509)  at io.netty.handler.ssl.SslHandler.wrap(SslHandler.java:1046)  at io.netty.handler.ssl.SslHandler.wrapNonAppData(SslHandler.java:937)  at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1395)  at io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1227)  at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1274)  at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:503)  at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:442)  at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:281)  at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)  at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)  at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)  at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1422)  at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)  at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)  at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:931)  at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)  at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:700)  at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:635)  at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:552)  at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:514)  at io.netty.util.concurrent.SingleThreadEventExecutor$6.run(SingleThreadEventExecutor.java:1050)  at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)  at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)  ... 1 common frames omitted 

这个异常是因为我的orderer节点在虚拟机上对外开放的端口是10050，但是服务发现在channel中获取到的是7050，因此sdk在使用我们提供的orderer节点的endpoint与orderer通讯的时候会失败，但是交易仍然会成功，原因是服务发现会将开发者手动加入到通道中的orderer节点与其查询出来的orderer节点的信息进行对比，如果两者不同，那么手动加入的orderer节点信息会被删除掉，采用服务发现自动获取的orderer节点。源码如图：

结合fabric网络分析：orderer节点在channel中广播的endpoint则是域名:LISTENPORT，那么service discovery在channel中查询到的orderer节点的endpoint就是域名:7050，因此在使用sdk开发application的时候需要注意一下。

如果demo测试过程中出现了问题，欢迎在本博客下留言，笔者会及时回复