系列文章目录

  1. Fabric2.2在Linux上的部署记录
  2. Fabric2.2测试网络(test-network)的使用记录
  3. 用go编写简单的fabric链码
  4. 将fabric链码部署到测试网络的记录
  5. 利用fabric-gateway-java连接并调用fabric链码

文章目录

前言

上一篇文章中记录了自定义链码的部署过程，并利用cli进行了调用。本文尝试利用fabric-gateway-java对链码进行调用。

一、fabric-gateway是什么？

根据官方文档的描述，fabric-gateway是提供给应用与fabric网络交互的SDK，用java来实现。fabric-gateway提供了简单的API，可以用最少的代码实现与链码的交互。

二、fabric-gateway使用流程

  • 配置钱包
  • 配置gateway
  • 获取网络
  • 获取合约
  • 调用合约

三、具体步骤

0 测试环境

版本
fabric2.2
fabric-gateway-java2.2
java8
platformcentos7.6

1 配置依赖

        <!-- 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>1.4.7</version>
        </dependency>

        <dependency>
            <groupId>org.hyperledger.fabric</groupId>
            <artifactId>fabric-gateway-java</artifactId>
            <version>2.2.0</version>
        </dependency>

2 配置connection.json文件

{
  "name": "basic-network",
  "version": "1.0.0",
  "dependencies": {
  },
  "client": {
    "organization": "Org1",
    "connection": {
      "timeout": {
        "peer": {
          "endorser": "300"
        },
        "orderer": "300"
      }
    }
  },
  "channels": {
    "mychannel": {
      "orderers": [
        "orderer.example.com"
      ],
      "peers": {
        "peer0.org1.example.com": {
          "endorsingPeer": true,
          "chaincodeQuery": true,
          "ledgerQuery": true,
          "eventSource": true
        },
        "peer0.org2.example.com": {
          "endorsingPeer": true,
          "chaincodeQuery": true,
          "ledgerQuery": true,
          "eventSource": true
        }
      }
    }
  },
  "organizations": {
    "Org1": {
      "mspid": "Org1MSP",
      "peers": [
        "peer0.org1.example.com"
      ],
      "certificateAuthorities": [
        "ca-org1"
      ],
      "adminPrivateKeyPEM": {
        "path": "src/main/resources/crypto-config/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp/keystore/priv_sk"
      },
      "signedCertPEM": {
        "path": "src/main/resources/crypto-config/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp/signcerts/Admin@org1.example.com-cert.pem"
      }
    },
    "Org2": {
      "mspid": "Org2MSP",
      "peers": [
        "peer0.org2.example.com"
      ],
      "certificateAuthorities": [
        "ca-org2"
      ],
      "adminPrivateKeyPEM": {
        "path": "src/main/resources/crypto-config/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp/keystore/priv_sk"
      },
      "signedCertPEM": {
        "path": "src/main/resources/crypto-config/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp/signcerts/Admin@org2.example.com-cert.pem"
      }
    }
  },
  "orderers": {
    "orderer.example.com": {
      "url": "grpcs://192.168.56.101:7050",
      "mspid": "OrdererMSP",
      "grpcOptions": {
        "ssl-target-name-override": "orderer.example.com",
        "hostnameOverride": "orderer.example.com"
      },
      "tlsCACerts": {
        "path": "src/main/resources/crypto-config/ordererOrganizations/example.com/orderers/orderer.example.com/tls/ca.crt"
      },
      "adminPrivateKeyPEM": {
        "path": "src/main/resources/crypto-config/ordererOrganizations/example.com/users/Admin@example.com/msp/keystore/priv_sk"
      },
      "signedCertPEM": {
        "path": "src/main/resources/crypto-config/ordererOrganizations/example.com/users/Admin@example.com/msp/signcerts/Admin@example.com-cert.pem"
      }
    }
  },
  "peers": {
    "peer0.org1.example.com": {
      "url": "grpcs://192.168.56.101:7051",
      "grpcOptions": {
        "ssl-target-name-override": "peer0.org1.example.com",
        "hostnameOverride": "peer0.org1.example.com",
        "request-timeout": 120001
      },
      "tlsCACerts": {
        "path": "src/main/resources/crypto-config/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt"
      }
    },
    "peer0.org2.example.com": {
      "url": "grpcs://192.168.56.101:9051",
      "grpcOptions": {
        "ssl-target-name-override": "peer0.org2.example.com",
        "hostnameOverride": "peer0.org2.example.com",
        "request-timeout": 120001
      },
      "tlsCACerts": {
        "path": "src/main/resources/crypto-config/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt"
      }
    }
  },
  "certificateAuthorities": {
    "ca-org1": {
      "url": "https://192.168.56.101:7054",
      "grpcOptions": {
        "verify": true
      },
      "tlsCACerts": {
        "path": "src/main/resources/crypto-config/peerOrganizations/org1.example.com/ca/ca.org1.example.com-cert.pem"
      },
      "registrar": [
        {
          "enrollId": "admin",
          "enrollSecret": "adminpw"
        }
      ]
    },
    "ca-org2": {
      "url": "https://192.168.56.101:8054",
      "grpcOptions": {
        "verify": true
      },
      "tlsCACerts": {
        "path": "src/main/resources/crypto-config/peerOrganizations/org2.example.com/ca/ca.org2.example.com-cert.pem"
      },
      "registrar": [
        {
          "enrollId": "admin",
          "enrollSecret": "adminpw"
        }
      ]
    }
  }
}

注意：自行更换部署链码的ip，以及各个证书和私钥路径。
笔者的配置文件结构如下图所示：
在这里插入图片描述
其中，图中圈起来的文件为节点的配置文件，在链码部署后，用部署链码生成的同名文件进行替换，用于获取节点的认证信息。

3 配置fabric.config.properties文件

# 网络配置文件路径
networkConfigPath = src/main/resources/connection.json
# 用户证书路径
certificatePath = src/main/resources/crypto-config/peerOrganizations/org1.example.com/users/User1@org1.example.com/msp/signcerts/User1@org1.example.com-cert.pem
# 用户私钥路径
privateKeyPath = src/main/resources/crypto-config/peerOrganizations/org1.example.com/users/User1@org1.example.com/msp/keystore/priv_sk

# 通道名字
channelName = mychannel

# 链码名字
contractName = hello

注意自行更换通道名字和链码名字。

4 连接并调用链码

public class SdkDemo {

    public static void main(String[] args) {
        try {
            //获取相应参数
            Properties properties = new Properties();
            InputStream inputStream = SdkDemo.class.getResourceAsStream("/fabric.config.properties");
            properties.load(inputStream);

            String networkConfigPath = properties.getProperty("networkConfigPath");
            String channelName = properties.getProperty("channelName");
            String contractName = properties.getProperty("contractName");
            //使用org1中的user1初始化一个网关wallet账户用于连接网络
            String certificatePath = properties.getProperty("certificatePath");
            X509Certificate certificate = readX509Certificate(Paths.get(certificatePath));

            String privateKeyPath = properties.getProperty("privateKeyPath");
            PrivateKey privateKey = getPrivateKey(Paths.get(privateKeyPath));

            Wallet wallet = Wallets.newInMemoryWallet();
            wallet.put("user1",Identities.newX509Identity("Org1MSP",certificate,privateKey));

            //根据connection.json 获取Fabric网络连接对象
            Gateway.Builder builder = Gateway.createBuilder()
                    .identity(wallet, "user1")
                    .networkConfig(Paths.get(networkConfigPath));
            //连接网关
            Gateway gateway = builder.connect();
            //获取通道
            Network network = gateway.getNetwork(channelName);
            //获取合约对象
            Contract contract = network.getContract(contractName);
            //查询现有资产
            //注意更换调用链码的具体函数
            byte[] queryAllAssets = contract.evaluateTransaction("GetAllAssets");
            System.out.println("所有资产："+new String(queryAllAssets, StandardCharsets.UTF_8));

            // 增加新的资产
            byte[] invokeResult = contract.createTransaction("CreateAsset")
                    .setEndorsingPeers(network.getChannel().getPeers(EnumSet.of(Peer.PeerRole.ENDORSING_PEER)))
                    .submit("asset5", "LaoWang", "666");
            System.out.println(new String(invokeResult, StandardCharsets.UTF_8));

            //查询更新后的资产
            byte[] queryAllAssetsAfter = contract.evaluateTransaction("GetAllAssets");
            System.out.println("更新资产："+new String(queryAllAssetsAfter, StandardCharsets.UTF_8));

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    private static X509Certificate readX509Certificate(final Path certificatePath) throws IOException, CertificateException {
        try (Reader certificateReader = Files.newBufferedReader(certificatePath, StandardCharsets.UTF_8)) {
            return Identities.readX509Certificate(certificateReader);
        }
    }

    private static PrivateKey getPrivateKey(final Path privateKeyPath) throws IOException, InvalidKeyException {
        try (Reader privateKeyReader = Files.newBufferedReader(privateKeyPath, StandardCharsets.UTF_8)) {
            return Identities.readPrivateKey(privateKeyReader);
        }
    }
}

到此步，应该可以成功利用gateway调用fabric链码，注意实际操作时应先启动网络并更换项目里的节点配置文件ordererOrganizations和peerOrganizations。

总结

在这篇文章中，记录了利用fabric-gateway-java调用部署好的fabric链码的过程，gateway提供的调用方法较为简单，详细的内容可参考官方文档。以上内容如有不正，请多多指教。

# 区块链 # java
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