Java chaincode¶
Note: This guide generally assumes you have followed the Chaincode development environment setup tutorial here.
To get started developing Java chaincode¶
- Ensure you have gradle
- Download the binary distribution from http://gradle.org/gradle-download/
- Unpack, move to the desired location, and add gradle’s bin directory to your system path
- Ensure
gradle -v
works from the command-line, and shows version 2.12 or greater - Optionally, enable the gradle daemon for faster builds
- Ensure you have the Java 1.8 JDK installed. Also ensure Java’s
directory is on your path with
java -version
- Additionally, you will need to have the
`JAVA HOME
<https://docs.oracle.com/cd/E19182-01/821-0917/6nluh6gq9/index.html>`__ variable set to your JDK installation in your system path
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
Build and run the peer process.
cd $GOPATH/src/github.com/hyperledger/fabric make peer peer node start
The following steps is for deploying chaincode in non-dev mode.
- Deploy the chaincode,
peer chaincode deploy -l java -p /opt/gopath/src/github.com/hyperledger/fabric/examples/chaincode/java/SimpleSample -c '{"Args": ["init", "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,
peer chaincode invoke -l java \
-n 6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9 \
-c '{"Args": ["transfer", "a", "b", "10"]}'
c7dde1d7-fae5-4b68-9ab1-928d61d1e346
- Query the values of a and b after the transfer
peer chaincode query -l java \
-n 6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9 \
-c '{ "Args": ["query", "a"]}'
{"Name":"a","Amount":"80"}
peer chaincode query -l java \
-n 6d9a704d95284593fe802a5de89f84e86fb975f00830bc6488713f9441b835cf32d9cd07b087b90e5cb57a88360f90a4de39521a5595545ad689cd64791679e9 \
-c '{ "Args": ["query", "b"]}'
{"Name":"b","Amount":"220"}
Java chaincode deployment in DEV Mode¶
Follow the step 1 to 3 as above,
Build and run the peer process
cd $GOPATH/src/github.com/hyperledger/fabric make peer peer node start --peer-chaincodedev
Open the second Vagrant terminal and build the Java shim layer and publish it to Local Maven Repo
cd $GOPATH/src/github.com/hyperledger/fabric/core/chaincode/shim/java gradle -b build.gradle clean gradle -b build.gradle build
Change to examples folder to build and run,
cd $GOPATH/src/github.com/hyperledger/fabric/examples/chaincode/java/SimpleSample gradle -b build.gradle build
Run the SimpleSample chaincode using the
gradle -b build.gradle run
Open the third Vagrant terminal to run init and invoke on the chaincode
peer chaincode deploy -l java -n SimpleSample -c ‘{“Args”: [“init”, “a”,”100”, “b”, “200”]}’
2016/06/28 19:10:15 Load docker HostConfig: %+v &{[] [] [] [] false map[] [] false [] [] [] [] host { 0} [] { map[]} false [] 0 0 0 false 0 0 0 0 []} 19:10:15.461 [crypto] main -> INFO 002 Log level recognized 'info', set to INFO SimpleSample
peer chaincode invoke -l java -n SimpleSample -c ‘{“Args”: [“transfer”, “a”, “b”, “10”]}’
2016/06/28 19:11:13 Load docker HostConfig: %+v &{[] [] [] [] false map[] [] false [] [] [] [] host { 0} [] { map[]} false [] 0 0 0 false 0 0 0 0 []}
19:11:13.553 [crypto] main -> INFO 002 Log level recognized 'info', set to INFO
978ff89e-e4ef-43da-a9f8-625f2f6f04e5
peer chaincode query -l java -n SimpleSample -c '{ "Args": ["query", "a"]}'
2016/06/28 19:12:19 Load docker HostConfig: %+v &{[] [] [] [] false map[] [] false [] [] [] [] host { 0} [] { map[]} false [] 0 0 0 false 0 0 0 0 []}
19:12:19.289 [crypto] main -> INFO 002 Log level recognized 'info', set to INFO
{"Name":"a","Amount":"90"}
peer chaincode query -l java -n SimpleSample -c '{"Args": ["query", "b"]}'
2016/06/28 19:12:25 Load docker HostConfig: %+v &{[] [] [] [] false map[] [] false [] [] [] [] host { 0} [] { map[]} false [] 0 0 0 false 0 0 0 0 []}
19:12:25.667 [crypto] main -> INFO 002 Log level recognized 'info', set to INFO
{"Name":"b","Amount":"210"}
Developing new JAVA chaincode¶
- Create a new Java project structure.
- Use existing
build.grade
from any example JAVA Chaincode project likeexamples/chaincode/java/SimpleSample
. - Make your main class extend ChaincodeBase class and implement the following methods from base class.
public String run(ChaincodeStub stub, String function, String[] args)
public String query(ChaincodeStub stub, String function, String[] args)
public String getChaincodeID()
- Modify the
mainClassName
inbuild.gradle
to point to your new class. - Build this project using
gradle -b build.gradle build
- Run this chaincode after starting a peer in dev-mode as above using
gradle -b build.gradle run