How to Integrate Camunda Workflow Engine with Spring Boot: Step‑by‑Step Guide

Camunda Overview

Camunda is a flexible workflow and process automation framework. Its core is a native BPMN 2.0 engine that runs on the Java Virtual Machine and can be embedded in any Java application or runtime container.

Official site: https://www.camunda.org/

Getting started: https://docs.camunda.org/get-started/

Integrating Camunda

Follow these steps to integrate Camunda with a Spring Boot project.

Preparation

Use Camunda Automation Platform 7 Initializr (https://start.camunda.com/) to generate a project.

Extract the project and open it in IntelliJ IDEA.

Edit pom.xml to add Camunda dependencies:

<dependency>
    <groupId>org.camunda.connect</groupId>
    <artifactId>camunda-connect-core</artifactId>
</dependency>

<dependency>
    <groupId>org.camunda.bpm</groupId>
    <artifactId>camunda-engine-plugin-connect</artifactId>
</dependency>

If you need to downgrade the Spring Boot version, modify the dependencyManagement section in pom.xml as follows:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.6.4</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
        <dependency>
            <groupId>org.camunda.bpm</groupId>
            <artifactId>camunda-bom</artifactId>
            <version>7.15.0</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

Configure application.yaml (example excerpt):

spring.datasource.url: jdbc:h2:file:./camunda-h2-database

camunda.bpm.admin-user:
  id: transduck
  password: 111111

spring.datasource.url

sets the database for the workflow engine. camunda.bpm.admin-user defines the admin credentials.

Create a Simple Workflow

Define a data model:

public class model {
    private String message;
    private String name;
    // getters and setters omitted for brevity
    @Override
    public String toString() {
        return "" + message + ", " + name;
    }
}

Create a REST controller to receive messages:

@RequestMapping("/")
@RestController
public class controller {

    Logger logger = Logger.getLogger(this.getClass().getName());

    @PostMapping("/message")
    public model createMessage(@RequestBody model model) {
        logger.info("-------Message Creator Initialized-------");
        model m = new model();
        m.setMessage(model.getMessage());
        m.setName(model.getName());
        logger.info("Message created --> " + m.toString());
        return m;
    }
}

In Camunda Modeler, open resources/process.bpmn and add a User Task for inputting name and message, then a Service Task that calls the REST endpoint. Configure the Service Task connector with the HTTP details of the endpoint.

Run and Test

Start the Spring Boot application and open http://localhost:8080/. Log in with the admin credentials defined earlier.

Navigate to the Tasklist, add a simple filter, start the process, claim the user task, fill in the form fields, and complete it. The Service Task will invoke the REST controller, and you can verify the output in the console.

Conclusion

This guide demonstrates how to build a simple Camunda workflow with Spring Boot, covering project generation, dependency configuration, BPMN modeling, and runtime testing.