HyperLedger Fabric Java SDK - Wrinting the ChainCode Sample in Java

Question

I want to know the equivalent java code to use Fabric Java SDk for the go chaincode and a way to call it in the EndToEndIT.java test file.

How can I do that?

Comments

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Рекомендую и Вам

Answer 1

To get started developing Java chaincode

1. Ensure you have gradle
2. Download the binary distribution from http://gradle.org/gradle-download/
3. Unpack, move to the desired location, and add gradle’s bin directory to your system path
4. Ensure gradle -v works from the command-line, and shows version 2.12 or greater
5. Optionally, enable the gradle daemon for faster builds
6. Ensure you have the Java 1.8 JDK installed. Also ensure Java’s directory is on your path with java -version
7. Additionally, you will need to have the JAVA HOME variable set to your JDK installation in your system path

8. From your command line terminal, move to the devenv subdirectory of your workspace environment. Log into a Vagrant terminal by executing the following command:

   vagrant ssh

9. Build and run the peer process.

   cd $GOPATH/src/github.com/hyperledger/fabric make peer peer node start

10. The following steps is for deploying chaincode in non-dev mode.

    • Deploy the chaincode,

    peer chaincode deploy -l java -n map -p /opt/gopath/src/github.com/hyperledger/fabric/core/chaincode/shim/java -c '{"Function": "init", "Args": ["a","100", "b", "200"]}'

6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9

    * This command will give the 'name' for this chaincode, and use this value in all the further commands with the -n (name) parameter
    * PS. This may take a few minutes depending on the environment as it deploys the chaincode in the container,

• Invoke a transfer transaction,

    /opt/gopath/src/github.com/hyperledger/fabric/core/chaincode/shim/java$ peer chaincode invoke -l java \
    -n 6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9 \
    -c '{"Function": "transfer", "Args": ["a","b", "20"]}'

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• Query the values of a and b after the transfer

    /opt/gopath/src/github.com/hyperledger/fabric/core/chaincode/shim/java$ peer chaincode query -l java \
    -n 6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9 \
    -c '{"Function": "query", "Args": ["a"]}'
    {"Name":"a","Amount":"80"}
    /opt/gopath/src/github.com/hyperledger/fabric/core/chaincode/shim/java$ peer chaincode query -l java \
    -n 6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9 \
    -c '{"Function": "query", "Args": ["b"]}'
    {"Name":"b","Amount":"220"}

• To develop your own chaincodes, simply extend the Chaincode class (demonstrated in the SimpleSample Example under the examples package)

Source: https://openblockchain.readthedocs.io/en/latest/Setup/JAVAChaincode/

If you want to know about Java chaincode deployment in DEV Mode, visit the above link.

Answer 2

The following link: 

 https://github.com/hyperledger-archives/fabric/blob/master/core/chaincode/shim/java/src/main/java/example/Example.java 

gives a version of Chaincode in Java. Hope this helps :)