hyperledger fabric链码（java）编写以及调用

java链码的编写很容易，如下2个：pom以及java代码：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>mckay</groupId>
    <artifactId>test1</artifactId>
    <version>1.0-SNAPSHOT</version>


    <dependencies>
        <dependency>
            <groupId>org.hyperledger.fabric-chaincode-java</groupId>
            <artifactId>fabric-chaincode-shim</artifactId>
            <version>1.4.4</version>
            <exclusions>
                <exclusion>
                    <groupId>com.github.everit-org.json-schema</groupId>
                    <artifactId>org.everit.json.schema</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.1.0</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <finalName>chaincode</finalName>
                            <transformers>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>tech.test1.MyChaincode</mainClass>
                                </transformer>
                            </transformers>
                            <filters>
                                <filter>
                                    <!-- filter out signature files from signed dependencies, else repackaging fails with security ex -->
                                    <artifact>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

package tech.test1;
 
import com.google.protobuf.ByteString;
import io.netty.handler.ssl.OpenSsl;
import io.netty.util.internal.StringUtil;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hyperledger.fabric.shim.ChaincodeBase;
import org.hyperledger.fabric.shim.ChaincodeStub;
 
import java.util.List;
 
import static com.google.common.base.Charsets.UTF_8;
 
public class MyChaincode extends ChaincodeBase {
    private static Log _logger = LogFactory.getLog(MyChaincode.class);
    public static void main(String[] args) {
        System.out.println("OpenSSL avaliable: " + OpenSsl.isAvailable());
        new MyChaincode().start(args);
    }
 
    @Override
    public Response init(ChaincodeStub chaincodeStub) {
        return newSuccessResponse();
    }
 
    @Override
    public Response invoke(ChaincodeStub stub) {
        try {
            _logger.info("Invoke java simple chaincode");
            String func = stub.getFunction();
            List<String> 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<String> 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<String> 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());
    }
 
}

然后把一整个带pom文件的目录全部上传到fabric机器的chaincode目录下：

进入cli容器中(docker exec cli /bin/bash)，进行链码的安装和初始化：

peer chaincode install -n mckaytest1 -v 1.0 -p /opt/gopath/src/github.com/chaincode/test1 -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 mckaytest1 -v 1.0 -c '{"Args":["init"]}' -P "AND ('Org1MSP.peer')"

做些命令行级别的测试：

peer chaincode invoke -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 mckaytest1 -c '{"Args":["invoke","a","bb"]}'
peer chaincode invoke -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 mckaytest1 -c '{"Args":["query","a"]}'

当改动链码代码后，需要升级，此时执行如下：

#升级  1.1
peer chaincode install -n mckaytest1 -v 1.1 -p /opt/gopath/src/github.com/chaincode/test1 -l java
peer chaincode upgrade -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 mckaytest1 -v 1.1 -c '{"Args":["init"]}' -P "AND ('Org1MSP.peer')"

用java代码调用链码（调用端需要改下hosts文件，以便识别orderer这些fabric节点的ip）：

UserContext userContext = new UserContext();
userContext.setAffiliation("Org1");
userContext.setMspId("Org1MSP");
userContext.setAccount("李伟");
userContext.setName("admin");
Enrollment enrollment = UserUtils.getEnrollment(keyFolderPath, keyFileName, certFoldePath, certFileName);
userContext.setEnrollment(enrollment);
FabricClient fabricClient = new FabricClient(userContext);
Peer peer0 = fabricClient.getPeer("peer0.org1.example.com","grpcs://peer0.org1.example.com:7051",tlsPeerFilePath);
List<Peer> peers = new ArrayList<>();
peers.add(peer0);
Orderer order = fabricClient.getOrderer("orderer.example.com","grpcs://orderer.example.com:7050",tlsOrderFilePath);
String initArgs[] = {"a", "4444555555555"};
fabricClient.invoke("mychannel", TransactionRequest.Type.JAVA,"mckaytest1",order,peers,"invoke",initArgs);