Hyperledger Fabric 2.x Java區塊鏈應用

一、說明

在上一篇文章中 《Hyperledger Fabric 2.x 自定義智慧合約》 分享了智慧合約的安裝並使用 cli 客戶端進行合約的呼叫；本文將使用 Java 程式碼基於 fabric-gateway-java 進行區塊鏈網路的訪問與交易，並整合 SpringBoot 框架。

Fabric Gateway SDK 實現Fabric的程式設計模型，提供了一系列簡單的API給應用程式與Fabric區塊鏈網路進行互動；

網路拓撲圖：

應用程式將各自的網路互動委託給其閘道器，每個閘道器都瞭解網路通道拓撲，包括組織的多個Peer節點和排序節點，使應用程式專注於業務邏輯；Peer節點可以使用gossip協議在組織內部和組織之間相互通訊。

二、Mavn依賴

新增閘道器sdk的依賴：

<dependency>
        <groupId>org.hyperledger.fabric</groupId>
        <artifactId>fabric-gateway-java</artifactId>
        <version>2.2.3</version>
</dependency>

三、準備配置檔案

工程的目錄結構如下圖所示：

3.1. 準備網路證照

建立目錄 crypto-config 把 orderer 和 peer 節點的證照檔案複製進來。

證照檔案從 fabric-samples 的 test-network 目錄中複製 ordererOrganizations 與 peerOrganizations 資料夾：

3.2. 建立網路配置

建立檔案 connection.json 內容如下：

{
    "name": "basic-network",
    "version": "1.0.0",
    "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://192.168.28.134:7050",
            "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://192.168.28.134:7051",
            "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://192.168.28.134:9051",
            "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://192.168.28.134:7054",
            "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://192.168.28.134:8054",
            "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"
                }
            ]
        }
    }
}

需按實際情況修改url中的地址，內容中分別包含了 channels、organizations、orderers、peers、ca 的配置

3.3. SpringBoot配置

在 application.yml 中新增以下內容，用於訪問閘道器的相關配置：

fabric:
  # wallet資料夾路徑(自動建立)
  walletDirectory: wallet
  # 網路配置檔案路徑
  networkConfigPath: connection.json
  # 使用者證照路徑
  certificatePath: crypto-config/peerOrganizations/org1.example.com/users/User1@org1.example.com/msp/signcerts/User1@org1.example.com-cert.pem
  # 使用者私鑰路徑
  privateKeyPath: crypto-config/peerOrganizations/org1.example.com/users/User1@org1.example.com/msp/keystore/priv_sk
  # 訪問的組織名
  mspid: Org1MSP
  # 使用者名稱
  username: user1
  # 通道名字
  channelName: mychannel
  # 鏈碼名字
  contractName: mycc

四、連線合約

分別構建閘道器、通道和合約的Bean物件，程式碼如下：

/**
 * 連線閘道器
 */
@Bean
public Gateway connectGateway() throws IOException, InvalidKeyException, CertificateException {
        //使用org1中的user1初始化一個閘道器wallet賬戶用於連線網路
        Wallet wallet = Wallets.newFileSystemWallet(Paths.get(this.walletDirectory));
        X509Certificate certificate = readX509Certificate(Paths.get(this.certificatePath));
        PrivateKey privateKey = getPrivateKey(Paths.get(this.privateKeyPath));
        wallet.put(username, Identities.newX509Identity(this.mspid, certificate, privateKey));

        //根據connection.json 獲取Fabric網路連線物件
        Gateway.Builder builder = Gateway.createBuilder()
                        .identity(wallet, username)
                        .networkConfig(Paths.get(this.networkConfigPath));

        //連線閘道器
        return builder.connect();
}

/**
 * 獲取通道
 */
@Bean
public Network network(Gateway gateway) {
        return gateway.getNetwork(this.channelName);
}

/**
 * 獲取合約
 */
@Bean
public Contract contract(Network network) {
        return network.getContract(this.contractName);
}

五、合約呼叫

建立controller類，注入Contract物件呼叫合約方法：

@Resource
private Contract contract;

@Resource
private Network network;

@GetMapping("/getUser")
public String getUser(String userId) throws ContractException {
        byte[] queryAResultBefore = contract.evaluateTransaction("getUser",userId);
        return new String(queryAResultBefore, StandardCharsets.UTF_8);
}

@GetMapping("/addUser")
public String addUser(String userId, String userName, String money) throws ContractException, InterruptedException, TimeoutException {
        byte[] invokeResult = contract.createTransaction("addUser")
                        .setEndorsingPeers(network.getChannel().getPeers(EnumSet.of(Peer.PeerRole.ENDORSING_PEER)))
                        .submit(userId, userName, money);
        String txId = new String(invokeResult, StandardCharsets.UTF_8);
        return txId;
}

六、測試介面

呼叫介面 getUser：

http://127.0.0.1:9001/getUser?userId=1

返回：

{
  "money": 300,
  "name": "zlt",
  "userId": "1"
}

呼叫介面 addUser：

http://127.0.0.1:9001/addUser?userId=6&userName=test6&money=600

返回：

2ae291bb6a366b5ba01ad49e4237da8def9e9828cc2c982e8c49d4b763af0157

七、程式碼下載

gitee：https://gitee.com/zlt2000/my-fabric-application-java

github：https://github.com/zlt2000/my-fabric-application-java

掃碼關注有驚喜！