一、说明
为了持续地进行信息的更新,以及对账本进行管理(写入交易,进行查询等),区块链网络引入了智能合约来实现对账本的访问和控制;智能合约在 Fabric 中称之为 链码
,是区块链应用的业务逻辑。
本文分享如何使用 Java 语言开发智能合约,以及合约的安装与使用。
二、环境准备
1、部署好 Fabric
的测试网络,按照上一篇文章《Hyperledger Fabric 2.x 环境搭建》的内容执行第1至5步
- 启动好两个 peer 节点和一个 orderer 节点
- 创建好 mychannel 通道
2、在环境变量中配置好执行命令(bin)、配置(config)与MSP文件夹的路径: 执行 vim /etc/profile
添加以下内容:
export FABRIC_PATH=/opt/gopath/src/github.com/hyperledger/fabric-samples
export FABRIC_CFG_PATH=${FABRIC_PATH}/config/
export MSP_PATH=${FABRIC_PATH}/test-network/organizations
export CORE_PEER_TLS_ENABLED=true
export PATH=${FABRIC_PATH}/bin:$PATH
三、下载合约代码
gitee:https://gitee.com/zlt2000_admin/my-fabric-chaincode-java
github:https://github.com/zlt2000/my-fabric-chaincode-java
四、代码解析
在 Fabric 2.x
版本后的合约编写方式与旧版本略有不同,需要实现 ContractInterface
接口,下面是官方的一段说明:
4.1. pom.xml文件
配置远程仓库
<repositories>
<repository>
<id>central</id>
<url>http://maven.aliyun.com/nexus/content/groups/public/</url>
<releases>
<enabled>true</enabled>
</releases>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
<repository>
<id>jitpack.io</id>
<url>https://www.jitpack.io</url>
</repository>
<repository>
<id>artifactory</id>
<url>https://hyperledger.jfrog.io/hyperledger/fabric-maven</url>
</repository>
</repositories>
依赖合约sdk
<dependency>
<groupId>org.hyperledger.fabric-chaincode-java</groupId>
<artifactId>fabric-chaincode-shim</artifactId>
<version>${fabric-chaincode-java.version}</version>
</dependency>
通过插件 maven-shade-plugin
指定 mainClass
为 org.hyperledger.fabric.contract.ContractRouter
<build>
<sourceDirectory>src/main/java</sourceDirectory>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</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>org.hyperledger.fabric.contract.ContractRouter</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>
4.2. model
创建合约的数据对象 User
使用 @DataType
注解标识,定义三个字段 userId
、name
、money
使用 @Property
注解标识:
@DataType
public class User {
@Property
private final String userId;
@Property
private final String name;
@Property
private final double money;
public User(final String userId, final String name, final double money) {
this.userId = userId;
this.name = name;
this.money = money;
}
@Override
public boolean equals(final Object obj) {
if (this == obj) {
return true;
}
if ((obj == null) || (getClass() != obj.getClass())) {
return false;
}
User other = (User) obj;
return Objects.deepEquals(
new String[] {getUserId(), getName()},
new String[] {other.getUserId(), other.getName()})
&&
Objects.deepEquals(
new double[] {getMoney()},
new double[] {other.getMoney()});
}
@Override
public int hashCode() {
return Objects.hash(getUserId(), getName(), getMoney());
}
@Override
public String toString() {
return JSON.toJSONString(this);
}
public String getUserId() {
return userId;
}
public String getName() {
return name;
}
public double getMoney() {
return money;
}
}
4.3. 合约逻辑
- 合约类使用
@Contract
与@Default
注解标识,并实现ContractInterface
接口 - 合约方法使用
@Transaction
注解标识 - 包含3个交易方法:
init
、addUser
、transfer
- 包含2个查询方法:
getUser
、queryAll
@Contract(name = "mycc")
@Default
public class MyAssetChaincode implements ContractInterface {
public MyAssetChaincode() {}
/**
* 初始化3条记录
*/
@Transaction(intent = Transaction.TYPE.SUBMIT)
public void init(final Context ctx) {
addUser(ctx, "1", "zlt",100D);
addUser(ctx, "2", "admin",200D);
addUser(ctx, "3", "guest",300D);
}
/**
* 新增用户
*/
@Transaction(intent = Transaction.TYPE.SUBMIT)
public User addUser(final Context ctx, final String userId, final String name, final double money) {
ChaincodeStub stub = ctx.getStub();
User user = new User(userId, name, money);
String userJson = JSON.toJSONString(user);
stub.putStringState(userId, userJson);
return user;
}
/**
* 查询某个用户
*/
@Transaction(intent = Transaction.TYPE.EVALUATE)
public User getUser(final Context ctx, final String userId) {
ChaincodeStub stub = ctx.getStub();
String userJSON = stub.getStringState(userId);
if (userJSON == null || userJSON.isEmpty()) {
String errorMessage = String.format("User %s does not exist", userId);
throw new ChaincodeException(errorMessage);
}
User user = JSON.parseObject(userJSON, User.class);
return user;
}
/**
* 查询所有用户
*/
@Transaction(intent = Transaction.TYPE.EVALUATE)
public String queryAll(final Context ctx) {
ChaincodeStub stub = ctx.getStub();
List<User> userList = new ArrayList<>();
QueryResultsIterator<KeyValue> results = stub.getStateByRange("", "");
for (KeyValue result: results) {
User user = JSON.parseObject(result.getStringValue(), User.class);
System.out.println(user);
userList.add(user);
}
return JSON.toJSONString(userList);
}
/**
* 转账
* @param sourceId 源用户id
* @param targetId 目标用户id
* @param money 金额
*/
@Transaction(intent = Transaction.TYPE.SUBMIT)
public void transfer(final Context ctx, final String sourceId, final String targetId, final double money) {
ChaincodeStub stub = ctx.getStub();
User sourceUser = getUser(ctx, sourceId);
User targetUser = getUser(ctx, targetId);
if (sourceUser.getMoney() < money) {
String errorMessage = String.format("The balance of user %s is insufficient", sourceId);
throw new ChaincodeException(errorMessage);
}
User newSourceUser = new User(sourceUser.getUserId(), sourceUser.getName(), sourceUser.getMoney() - money);
User newTargetUser = new User(targetUser.getUserId(), targetUser.getName(), targetUser.getMoney() + money);
stub.putStringState(sourceId, JSON.toJSONString(newSourceUser));
stub.putStringState(targetId, JSON.toJSONString(newTargetUser));
}
}
五、打包合约代码
把合约源代码打包成压缩文件,用于后续安装:
peer lifecycle chaincode package mycc.tar.gz --path /opt/app/my-fabric-chaincode-java --lang java --label mycc
六、安装合约
在指定 peer 节点上安装链码,下面分别为两个机构安装。
6.1. 为机构peer0.org1安装合约
执行以下命令,设置 peer0.org1
环境:
export CORE_PEER_LOCALMSPID="Org1MSP"
export CORE_PEER_TLS_ROOTCERT_FILE=${MSP_PATH}/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt
export CORE_PEER_MSPCONFIGPATH=${MSP_PATH}/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp
export CORE_PEER_ADDRESS=localhost:7051
执行以下命令安装:
peer lifecycle chaincode install mycc.tar.gz
成功后返回:
2022-02-09 22:09:13.498 EST 0001 INFO [cli.lifecycle.chaincode] submitInstallProposal -> Installed remotely: response:<status:200 payload:"\nEmycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae\022\004mycc" >
2022-02-09 22:09:13.498 EST 0002 INFO [cli.lifecycle.chaincode] submitInstallProposal -> Chaincode code package identifier: mycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae
6.2. 为机构peer0.org2安装合约
执行以下命令,设置 peer0.org2
环境:
export CORE_PEER_LOCALMSPID="Org2MSP"
export CORE_PEER_TLS_ROOTCERT_FILE=${MSP_PATH}/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt
export CORE_PEER_MSPCONFIGPATH=${MSP_PATH}/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp
export CORE_PEER_ADDRESS=localhost:9051
执行以下命令安装:
peer lifecycle chaincode install mycc.tar.gz
成功后返回:
2022-02-09 22:14:14.862 EST 0001 INFO [cli.lifecycle.chaincode] submitInstallProposal -> Installed remotely: response:<status:200 payload:"\nEmycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae\022\004mycc" >
2022-02-09 22:14:14.862 EST 0002 INFO [cli.lifecycle.chaincode] submitInstallProposal -> Chaincode code package identifier: mycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae
查看安装的合约清单:
peer lifecycle chaincode queryinstalled
返回合约的 Package ID
与 Label
:
Installed chaincodes on peer:
Package ID: mycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae, Label: mycc
七、审批合约
当合约安装后,需经过机构的审批达成一致后才允许使用。
7.1. 为机构peer0.org1审批合约定义
执行以下命令,设置 peer0.org1
环境:
export CORE_PEER_LOCALMSPID="Org1MSP"
export CORE_PEER_TLS_ROOTCERT_FILE=${MSP_PATH}/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt
export CORE_PEER_MSPCONFIGPATH=${MSP_PATH}/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp
export CORE_PEER_ADDRESS=localhost:7051
执行以下命令审批合约:
peer lifecycle chaincode approveformyorg \
-o localhost:7050 \
--ordererTLSHostnameOverride orderer.example.com \
--tls
--cafile ${MSP_PATH}/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem \
--channelID mychannel \
--name mycc \
--version 1.0 \
--package-id mycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae \
--sequence 1
成功后返回:
2022-02-09 22:22:38.403 EST 0001 INFO [chaincodeCmd] ClientWait -> txid [2531db2811945a641947000cb15cfd19e0b72da594dfba994f5f79b6bc51bce2] committed with status (VALID) at localhost:7051
7.2. 为机构peer0.org2审批合约定义
执行以下命令,设置 peer0.org2
环境:
export CORE_PEER_LOCALMSPID="Org2MSP"
export CORE_PEER_TLS_ROOTCERT_FILE=${MSP_PATH}/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt
export CORE_PEER_MSPCONFIGPATH=${MSP_PATH}/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp
export CORE_PEER_ADDRESS=localhost:9051
执行以下命令审批合约:
peer lifecycle chaincode approveformyorg \
-o localhost:7050 \
--ordererTLSHostnameOverride orderer.example.com \
--tls \
--cafile ${MSP_PATH}/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem \
--channelID mychannel \
--name mycc \
--version 1.0 \
--package-id mycc:4c8dce2c7f746d26293ca8f27a3ccdec8d6438090f873f40f8ac9508c01973ae \
--sequence 1
成功后返回:
2022-02-09 22:22:47.711 EST 0001 INFO [chaincodeCmd] ClientWait -> txid [796a1e0a735e69425bcd5911bdf4b2a8003bbac977c5e60c769f84da6b86ef86] committed with status (VALID) at localhost:9051
7.3. 合约提交检查
检查合约的审批情况,是否可以向通道进行提交:
peer lifecycle chaincode checkcommitreadiness --channelID mychannel --name mycc --version 1.0 --sequence 1 --output json
返回:
{
"approvals": {
"Org1MSP": true,
"Org2MSP": true
}
}
八、提交合约
执行以下命令,向通道提交合约:
peer lifecycle chaincode commit \
-o localhost:7050 \
--ordererTLSHostnameOverride orderer.example.com \
--tls \
--cafile ${MSP_PATH}/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem \
--channelID mychannel \
--name mycc \
--peerAddresses localhost:7051 \
--tlsRootCertFiles ${MSP_PATH}/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt \
--peerAddresses localhost:9051 \
--tlsRootCertFiles ${MSP_PATH}/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt \
--version 1.0 \
--sequence 1
成功后返回:
2022-02-09 22:22:57.445 EST 0001 INFO [chaincodeCmd] ClientWait -> txid [97ded758675113b9339dc9b378a13c0790ea3780855bb8f651758bfb007fc1ec] committed with status (VALID) at localhost:7051
2022-02-09 22:22:57.456 EST 0002 INFO [chaincodeCmd] ClientWait -> txid [97ded758675113b9339dc9b378a13c0790ea3780855bb8f651758bfb007fc1ec] committed with status (VALID) at localhost:9051
查看通道上已经提交的合约:
peer lifecycle chaincode querycommitted --channelID mychannel --name mycc --output json
返回:
{
"sequence": 1,
"version": "1.0",
"endorsement_plugin": "escc",
"validation_plugin": "vscc",
"validation_parameter": "EiAvQ2hhbm5lbC9BcHBsaWNhdGlvbi9FbmRvcnNlbWVudA==",
"collections": {},
"approvals": {
"Org1MSP": true,
"Org2MSP": true
}
}
九、测试智能合约
- 交易数据使用
peer chaincode invoke [flags]
命令,该命令将尝试向网络提交背书过的交易。 - 查询数据使用
peer chaincode query [flags]
,该命令不会生成交易。
由于 invoke
命令所需要的参数较多,所以我们先创建一个脚本命令。 执行 vim invoke.sh
添加以下内容:
peer chaincode invoke -o localhost:7050 \
--ordererTLSHostnameOverride orderer.example.com \
--tls \
--cafile ${MSP_PATH}/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem \
-C mychannel \
-n mycc \
--peerAddresses localhost:7051 \
--tlsRootCertFiles ${MSP_PATH}/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt \
--peerAddresses localhost:9051 \
--tlsRootCertFiles ${MSP_PATH}/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt \
-c ${1}
9.1. 初始化账本
执行以下命令,调用合约的 init
方法初始化3条账本记录:
sh invoke.sh '{"function":"init","Args":[]}'
9.2. 查询数据
执行以下命令,设置 peer0.org1
环境:
export CORE_PEER_LOCALMSPID="Org1MSP"
export CORE_PEER_TLS_ROOTCERT_FILE=${MSP_PATH}/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt
export CORE_PEER_MSPCONFIGPATH=${MSP_PATH}/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp
export CORE_PEER_ADDRESS=localhost:7051
执行下面命令,调用 queryAll
方法,查询所有数据:
peer chaincode query -C mychannel -n mycc -c '{"Args":["queryAll"]}'
执行后返回3条数据的数组:
[{"money":100.0,"name":"zlt","userId":"1"},{"money":200.0,"name":"admin","userId":"2"},{"money":300.0,"name":"guest","userId":"3"}]
执行下面命令,调用 getUser
方法传入 1
参数,查询单个数据:
peer chaincode query -C mychannel -n mycc -c '{"Args":["getUser", "1"]}'
执行后返回id为1的数据:
{"money":100,"name":"zlt","userId":"1"}
9.3. 新增数据
执行以下命令,调用 addUser
方法,新增一条id为4的记录:
sh invoke.sh '{"function":"addUser","Args":["4","test","400"]}'
9.4. 转账
执行以下命令,调用 transfer
方法,进行转账操作:
sh invoke.sh '{"function":"transfer","Args":["4","1","400"]}'
转账成功后,使用查询命令进行查看:
peer chaincode query -C mychannel -n mycc -c '{"Args":["queryAll"]}'
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