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 usage of application.yaml configuration file and contains couple of integration tests, showing how this can be tested.

How is it done

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

...
<dependency>
 <groupId>org.camunda.bpm.springboot</groupId>
 <artifactId>camunda-bpm-spring-boot-starter</artifactId>
 <version>2.3.0-SNAPSHOT</version>
</dependency>
...

2. With Spring Boot you usually create "application" class annotated with @SpringBootApplication. In order to have Camunda process application registered, you can simply add annotation @EnableProcessApplication to the same class and also include 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 engine services in your Spring beans using @Autowired annotation.

Run the application and check the result

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

Observe 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}