How to Implement Activiti Event Listeners in Spring Boot: Task and Process Events

This article continues the previous two parts and focuses on using Activiti events within a Spring Boot application.

Event listeners

The main listener interfaces are TaskRuntimeEventListeners for task events and ProcessRuntimeEventListener for process events, both handling RuntimeEvent objects.

TaskAssignedEvent (task assignment) example:

<code>@Configuration
public class EventListenerConfig {
  private static Logger logger = LoggerFactory.getLogger(EventListenerConfig.class);

  @Bean
  public TaskRuntimeEventListener&lt;TaskAssignedEvent&gt; taskAssignedListener() {
    return taskAssignedEvent -> {
      logger.info("BusinessKey: {}", taskAssignedEvent.getBusinessKey());
      Task task = taskAssignedEvent.getEntity();
      logger.info("task, id: {}, name: {}, assignee: {}", task.getId(), task.getName(), task.getAssignee());
      logger.info("ProcessDefinitionId: {}", taskAssignedEvent.getProcessDefinitionId());
    };
  }
}
</code>

The listener logs task assignment details; you can extend it for more complex business logic.

Testing the task assignment:

Start a task via /holidays/start?processDefinitionId=holiday:1:65d9157a-61e6-11eb-aa1f-00d861e5b732&userId=10000 , which assigns the task to user 10000.

Console output shows the logged assignment information, confirming the listener works.

Next, call /holidays/apply?days=3&mgr=10001&explain=生病&instanceId=306224db-61e7-11eb-aa1f-00d861e5b732 to move the task to the department manager.

TaskCompletedEvent (task completion) example:

<code>@Bean
public TaskRuntimeEventListener&lt;TaskCompletedEvent&gt; taskCompletedEvent() {
  return taskCompletedEvent -> {
    logger.info("BusinessKey: {}", taskCompletedEvent.getBusinessKey());
    Task task = taskCompletedEvent.getEntity();
    logger.info("task, id: {}, name: {}, owner: {}", task.getId(), task.getName(), task.getOwner());
  };
}
</code>

Resulting console output after completing the task confirms the listener execution.

ProcessRuntimeEventListener for process events, e.g., ProcessCompletedEvent :

<code>@Bean
public ProcessRuntimeEventListener&lt;ProcessCompletedEvent&gt; processCompletedEvent() {
  return processCompletedEvent -> {
    ProcessInstance instance = processCompletedEvent.getEntity();
    logger.info("任务发起人：{}", instance.getInitiator());
  };
}
</code>

This listener is invoked when a process finishes, logging the initiator of the workflow.

Note: If you start the process using the previous code, the initiator may be null . To set it correctly, modify the service method that starts the process:

<code>public void startProcessInstanceAssignVariables(String processDefinitionId, Map&lt;String, Object&gt; variables) {
  Authentication.setAuthenticatedUserId((String)variables.get("assignee"));
  ProcessInstance processInstance = runtimeService.startProcessInstanceById(processDefinitionId, variables);
  logger.info("流程定义ID: {}", processInstance.getProcessDefinitionId());
  logger.info("流程实例ID: {}", processInstance.getId());
  logger.info("BussinessKey: {}", processInstance.getBusinessKey());
}
</code>

Here, Authentication.setAuthenticatedUserId sets the user who initiates the task, which is later available in the process completion listener.

After the workflow finishes, you can verify the data in the act_hi_procinst table, which now contains values for the completed process.

All listeners work as expected, and the workflow completes successfully.