Spring Boot NATS Example

This examples demonstrates how to use the Java NATS client with Spring Boot by providing a NATS to web gateway. This allows you watch all published NATS messages in your browser. Cloud Foundry uses NATS for distributing messages.

To run this example, you will need Java, Maven, and Ruby installed.

Install NATS

To use this example, you will need to have NATS installed. To install NATS simply run (assuming you have Ruby installed with the proper permissions to install Ruby Gems) from a terminal:

$ gem install nats

To test your NATS server, make sure you can run:

$ nats-server

Install Java NATS Client

The support for using Spring's Java config in the Java NATS client hasn't yet been pushed up to Maven Central, so you will need to check out the Java NATS client and compile it.

$ git clone https://github.com/cloudfoundry-community/java-nats.git
$ cd java-nats
$ mvn install

Compile and run Spring Boot NATS Example

Now you need the code for this example. Simply clone it and compile it.

$ git clone https://github.com/mheath/spring-boot-nats-example
$ cd spring-boot-nats-example
$ mvn package

Now to run the example, you don't need an application server or any kind of servlet container. We're using Spring Boot so you can simply run:

$ java -jar target/spring-boot-nats-example-0.1-SNAPSHOT.jar

You should see some logs indicating the the example has started.

To make sure the example is working, open another terminal and run:

$ nats-pub test "This is a test."

You should see in the example terminal that it received a NATS message.

Now point your browser to 'http://localhost:8080' and publish more NATS messages doing:

$ nats-pub spring "Spring Boot rocks."
$ nats-pub some.other.subject "Cloud Foundry makes me happy."
$ nats-pub heath "Mike Heath is my hero."

You should see each of these NATS messages appear in your browser. If you're using Chrome, Chrome will buffer the first 1k or so of the response before showing anything so you will have to publish a bunch of NATS messages before Chrome will start displaying them. Because of this, I recommend using a true geek's web browser, curl.

Now look at the source code of the example and bask in the fact that it's a single source file with less than 75 lines.