hyperledger fabric 1.4 使用使用java开发智能合约 开发智能合约 hyperledger fabric使用java开发智能合约，也较为简单，我们今天就来聊一聊如何使用java开发智能合约，如需完整的学习fabric，可以参考视频教程 首先需要在pom里面引入fabric的智能合约的jar包，如下图所示，需要注意的点如下，引入maven-shade-plugin包，设置mainclass，且finalname必须为 chaincode。 org.hyperledger.fabric-chaincode-java fabric-chaincode-shim 1.4.0 org.apache.maven.plugins maven-compiler-plugin 3.1 ${java.version} ${java.version} org.apache.maven.plugins maven-shade-plugin 3.1.0 package shade chaincode com.fabric.chaincode.MyChaincode *:* META-INF/*.SF META-INF/*.DSA META-INF/*.RSA ``` java-fabric的示例代码如下： public class MyChaincode extends ChaincodeBase { private static Log _logger = LogFactory.getLog(MyChaincode.class); @Override public Response init(ChaincodeStub stub) { return newSuccessResponse(); } @Override public Response invoke(ChaincodeStub stub) { try { _logger.info("Invoke java simple chaincode"); String func = stub.getFunction(); List params = stub.getParameters(); if (func.equals("invoke")) { return invoke(stub, params); } else if (func.equals("query")) { return query(stub, params); } return newErrorResponse("Invalid invoke function name. Expecting one of: [\"invoke\", \"delete\", \"query\"]"); } catch (Throwable e) { return newErrorResponse(e); } } private Response invoke(ChaincodeStub stub, List args) { if (args.size() != 2) { return newErrorResponse("Incorrect number of arguments. Expecting 3"); } String key = args.get(0); String json = args.get(1); if(StringUtil.isNullOrEmpty(key) || StringUtil.isNullOrEmpty(json)){ return newErrorResponse("arguments error"); }else{ stub.putStringState(key,json); return newSuccessResponse("put success!"); } } // query callback representing the query of a chaincode private Response query(ChaincodeStub stub, List args) { if (args.size() != 1) { return newErrorResponse("Incorrect number of arguments. Expecting name of the person to query"); } String key = args.get(0); //byte[] stateBytes String val = stub.getStringState(key); if (val == null) { return newErrorResponse(String.format("Error: state for %s is null", key)); } _logger.info(String.format("Query Response:\nName: %s, Amount: %s\n", key, val)); return newSuccessResponse(val, ByteString.copyFrom(val, UTF_8).toByteArray()); } public static void main(String[] args) { 

System.out.println("OpenSSL avaliable: " OpenSsl.isAvailable()); new MyChaincode().start(args); } } 智能合约的安装和实例化,需要注意的是 -l java指定java语言为智能合约，智能合约的路径需要补全，go开发的话无需补全。 peer chaincode install -n jcode -v 1.0 -p /opt/gopath/src/github.com/chaincode/javachaincode/ -l java peer chaincode instantiate -o orderer.example.com:7050 –tls –cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com- cert.pem -C mychannel -n jcode -v 1.0 -c ‘{“Args”:[“init”]}’ -P “AND (‘Org1MSP.peer’)”` 遨游技术，享受生活 作者：桃猿结义