Bitcoind Json Rpc Client for Java

This is a Java library to call the Json Rpc API of the reference implementation Bitcoind. The goal is to support all methods listed in the ./bitcoind help-command. The implementation started from version 0.8.3 of Bitcoind and will not support previous versions. For further details about the implemented API visit the bitcoin.org wiki. Currently tested version is 0.9.0.

Build

Having OpenJDK 7 and Maven 3 installed, execute:

  mvn clean install

Usage

Maven will need to know where to search for this artifact. Add this to your pom.xml:

    <repository>
      <id>BitcoindClient4j</id>
      <name>GitHub BitcoindClient4j Repository</name>
      <url>https://s3.amazonaws.com/37mvnrepo/release</url>
    </repository>

Then add the dependency itself:

    <dependency>
      <groupId>com.37coins</groupId>
      <artifactId>BitcoindClient4J</artifactId>
      <version>0.2.2</version>
    </dependency>

Having dependencies resolved, you can code away. First initialize the Factory with network parameters:

  BitcoindClientFactory clientFactory = 
      new BitcoindClientFactory(
          new URL("http://localhost:8332/"), 
          "user", 
          "password");

Then get a client instance:

  BitcoindInterface client = clientFactory.getClient();

Now you can make calls to your node:

  Info info = client.getinfo();

If you had the API start your bitcoind, you might be interested in stopping it again:

  client.stop();

Blockchain Events

The library also captures notifications from Bitcoind using the startup configuration. Launch your deamon with those parameters:

  ./bitcoind  -blocknotify="echo '%s' | nc 127.0.0.1 4001" 
              -walletnotify="echo '%s' | nc 127.0.0.1 4002" 
              -alertnotify="echo '%s' | nc 127.0.0.1 4003" 
              -daemon

Or, if you have your bitcoind locally, have the API start up the daemon. Call the factory with a path instead of network parameters:

  BitcoindClientFactory clientFactory = 
      new BitcoindClientFactory(
          "/home/user/.bitcoin/",
          Arrays.asList("./bitcoind"));

You can register observers to capture events about blocks, addresses in you wallet, and alerts:

  new BlockListener(client).addObserver(new Observer() {
    @Override
    public void update(Observable o, Object arg) {
      Block block = (Block)arg;
    }
  });

Make sure to close sockets later:

  blockListener.stop();

Donations

Bitcoin donations can be sent to:

  152jsQJyQwxRywuHVVGLFEHkZqJ4QzuFS3

Thanks!

License

GPL3, see LICENSE.txt