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    Blockchain as a Service:Use Fabric Java SDK

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    Blockchain as a Service:Use Fabric Java SDK

    Last Updated:Apr 29, 2020

    Install java and maven

    The sample program relies on the Java 1.8 runtime environment and Maven, which can be confirmed by the following command.

    1. $ mvn -version
    2. Apache Maven 3.5.3 (3383c37e1f9e9b3bc3df5050c29c8aff9f295297; 2018-02-25T03:49:05+08:00)
    3. ...
    4. Java version: 1.8.0_161, vendor: Oracle Corporation

    Download sample program

    Please download java-sdk-demo-1.4.5. After downloading and extracting, copy the SDK configuration file connection-profile-standard.yaml to java-sdk-demo.

    The final directory structure is as follows:

    java sdk source

    Install dependencies

    It contains the jar file of the fabric-sdk-java and the corresponding source package. Can be installed by the following:

    java-sdk-demo-1.4.5 run following commands:

    1. mvn install:install-file -Dfile=./lib/fabric-sdk-java-1.4.5-jar-with-dependencies.jar -DgroupId=org.hyperledger.fabric-sdk-java -DartifactId=fabric-sdk-java -Dversion=1.4.5 -Dpackaging=jar
    2. mvn install:install-file -Dfile=./lib/fabric-sdk-java-1.4.5-sources.jar -DgroupId=org.hyperledger.fabric-sdk-java -DartifactId=fabric-sdk-java -Dversion=1.4.5 -Dpackaging=jar -Dclassifier=sources

    Deploy chaincode

    Upload the chaincode chaincode/sacc.out to BaaS and instantiate it. For the upload method, please see Deploy Chaincode.

    Running the sample program

    Open a Java IDE (Take IDEA for example) and import the java-sdk-demo project.

    Open the file src/main/java/com/aliyun/baas/Main.java, modify the value of the following variables.

    • channelName: the name of the channel, such as “first-channel”.
    • userName: Username.
    • secret: User’s password. If you forget the password, you can reset the password at first.
    • chaincodeName: The chaincode name. If you use sacc.out, please enter sacc.
    • chaincodeVersion: The version of the chaincode. If you use sacc.out, please enter 1.0.0.

    after modification, run com.aliyun.baas.Main as main class:

    java sdk

    This sample program based on Hyperledger Fabric java SDK, mainly to help you understand the basic use of the java SDK, which demonstrates the following:

    1. Enroll user.
    2. Read the configuration file, connect to the channel-related peer, and listen for block events.
    3. Get the block information of the ledger and print to console.
    4. Invoke the sacc chaincode, write a new ledger record, and read it.
    5. Disconnect from the peer.

    More instructions on using the Java SDK can be found at fabric-sdk-java.