Hyperledger Fabric 2.x Java区块链应用

一、说明

在上一篇文章中 《Hyperledger Fabric 2.x 自定义智能合约》 分享了智能合约的安装并使用 cli 客户端进行合约的调用；本文将使用 Java 代码基于 fabric-gateway-java 进行区块链网络的访问与交易，并集成 SpringBoot 框架。

Fabric Gateway SDK 实现Fabric的编程模型，提供了一系列简单的API给应用程序与Fabric区块链网络进行交互；

网络拓扑图：

应用程序将各自的网络交互委托给其网关，每个网关都了解网络信道拓扑，包括组织的多个Peer节点和排序节点，使应用程序专注于业务逻辑；Peer节点可以使用gossip协议在组织内部和组织之间相互通信。

二、Mavn依赖

添加网关sdk的依赖：

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

三、准备配置文件

工程的目录结构如下图所示：

3.1. 准备网络证书

创建目录 crypto-config 把 orderer 和 peer 节点的证书文件复制进来。

证书文件从 fabric-samples 的 test-network 目录中复制 ordererOrganizations 与 peerOrganizations 文件夹：

3.2. 创建网络配置

创建文件 connection.json 内容如下：

{
    "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"
                }
            ]
        }
    }
}

需按实际情况修改url中的地址，内容中分别包含了 channels、organizations、orderers、peers、ca 的配置

3.3. SpringBoot配置

在 application.yml 中添加以下内容，用于访问网关的相关配置：

fabric:
  # wallet文件夹路径(自动创建)
  walletDirectory: wallet
  # 网络配置文件路径
  networkConfigPath: connection.json
  # 用户证书路径
  certificatePath: 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: crypto-config/peerOrganizations/org1.example.com/users/User1@org1.example.com/msp/keystore/priv_sk
  # 访问的组织名
  mspid: Org1MSP
  # 用户名
  username: user1
  # 通道名字
  channelName: mychannel
  # 链码名字
  contractName: mycc

四、连接合约

分别构建网关、通道和合约的Bean对象，代码如下：

/**
 * 连接网关
 */
@Bean
public Gateway connectGateway() throws IOException, InvalidKeyException, CertificateException {
		//使用org1中的user1初始化一个网关wallet账户用于连接网络
		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));

		//根据connection.json 获取Fabric网络连接对象
		Gateway.Builder builder = Gateway.createBuilder()
						.identity(wallet, username)
						.networkConfig(Paths.get(this.networkConfigPath));

		//连接网关
		return builder.connect();
}

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

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

五、合约调用

创建controller类，注入Contract对象调用合约方法：

@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、测试接口

调用接口 getUser：

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

返回：

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

调用接口 addUser：

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

返回：

2ae291bb6a366b5ba01ad49e4237da8def9e9828cc2c982e8c49d4b763af0157

七、代码下载

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

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

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