example-simple

Simple Camunda Spring Boot Application

This example only uses camunda-bpm-spring-boot-starter, so it does not start an embedded tomcat and provides no REST API. It demonstrates how Camunda can be used in combination with Spring Boot to spawn a node that:

• connects to a database (and sets it up if needed, in this case h2 in memory db)
• configures and starts a process engine
• deploys the 'sample.bpmn' process
• starts this process
• automatically executes the user task
• JobExecutor executes async service task
• once the process instance is ended, the spring boot application terminates

It also demonstrates the usage of application.yaml configuration file and contains a couple of integration tests, showing how this can be tested.

How is it done

1. To embed Camunda Engine you must add the following dependency to your pom.xml:

...
<dependency>
 <groupId>org.camunda.bpm.springboot</groupId>
 <artifactId>camunda-bpm-spring-boot-starter</artifactId>
 <version>7.16.0</version>
</dependency>
...

2. With Spring Boot you usually create an "application" class annotated with @SpringBootApplication. In order to have a Camunda process application registered, you can simply add the annotation @EnableProcessApplication to the same class and also include the processes.xml file in your META-INF folder:

@SpringBootApplication
@EnableProcessApplication("mySimpleApplication")
public class SimpleApplication {

  public static void main(final String... args) throws Exception {
    SpringApplication.run(SimpleApplication.class, args);
  }

}

3. You can simply inject the engine services in your Spring beans using the @Autowired annotation.

Run the application and check the result

You can build the application with mvn clean install and then run it with the java -jar command.

Observe the log entries similar to these:

postDeploy: PostDeployEvent{processEngine=org.camunda.bpm.engine.impl.ProcessEngineImpl@6973b51b}
started instance: 0f1cd511-a1f0-11e7-8e5d-0a0027000006
completed task: Task[0f200964-a1f0-11e7-8e5d-0a0027000006]
executed sayHelloDelegate: ProcessInstance[380e1597-a206-11e7-8d39-0a0027000006]
processinstance ended!
preUndeploy: PreUndeployEvent{processEngine=org.camunda.bpm.engine.impl.ProcessEngineImpl@3be4ea5e}