Question

我正在尝试从Microsoft实施eventhub示例，以从事件中心接收事件 https://docs.microsoft.com/fr-fr/azure/event-hubs/event-hubs-java-get-started-receive-eph

我已经在Spring Boot应用程序中创建了这些类，并且能够打印出消息。

我想处理这些事件，所以我决定创建一个服务。 @Autowired无法从上下文加载服务。我不知道为什么；

@SpringBootApplication
    public class EventProcessorSample
{
    public static void main(String args[]) throws InterruptedException, ExecutionException
    {
############



        host.registerEventProcessor(EventProcessor.class, options)
        .whenComplete((unused, e) ->
        {


#######
        System.out.println("End of sample");
    }

问题在这里：服务为NULL 我已经尝试了@Component或@Service到此类。.但是未填充服务。

public static class EventProcessor implements IEventProcessor
{
    private int checkpointBatchingCount = 0;
@Autowired
ProcessingService processingservice;

    // onEvents is called when events are received on this partition of the Event Hub. 
    @Override
    public void onEvents(PartitionContext context, Iterable<EventData> events) throws Exception
    {
        System.out.println("SAMPLE: Partition " + context.getPartitionId() + " got event batch");
        int eventCount = 0;
        for (EventData data : events)
        {
            try
            {
                processingservice.process(new String(data.getBytes(), "UTF8"));

            }
            catch (Exception e)
            {
                System.out.println("Processing failed for an event: " + e.toString());
            }
        }
        System.out.println("SAMPLE: Partition " + context.getPartitionId() + " batch size was " + eventCount + " for host " + context.getOwner());
    }
}

服务：

@Service
public class ProcessingService {

public void process(String myMessage){
//Call Repository
}

}

是因为registerHostProcessor使用类类型作为参数吗？我如何加载服务以进行处理并随后调用存储库？

谢谢。

打包是简单的springboot应用程序

src/main/java
 |
 +-- EventProcessorSample
 |    
 +-- service
 |  |  
 |  +-- ProcessingService
 |    
 +-- processor
 |  |  
 |  +-- EventProcessor
 |    
 +-- repository
 |  |  
 +  |-- MyRepository

Answer 1

您需要从以下位置更改注册代码：

 host.registerEventProcessor(EventProcessor.class, options)

到

@Autowired
    private EventProcessorFactory eventProcessorFactory;
...
    host.registerEventProcessorFactory(eventProcessorFactory)

哪里

@Component
public class EventProcessorFactory implements IEventProcessorFactory<EventProcessor> {

    @Autowired
    ProcessingService processingservice;

    @Override
    public EventProcessor createEventProcessor(PartitionContext context) throws Exception {
        return new EventProcessor(processingservice);
    }

}

EventProcessorFactory是Spring管理生命周期的组件。您可以将所需的任何东西注入EventProcessorFactory，然后在工厂方法内创建EventProcessor时将其传递给EventProcessor。这样，您就可以开始控制EventProcessor实例的创建。

希望这会有所帮助！

Answer 2

您的EventProcessor类也应该是Spring bean-添加@Component并确保Spring的组件扫描机制可以找到带注释的类...

@Component
public class EventProcessor implements IEventProcessor
{
    private int checkpointBatchingCount = 0;
    private ProcessingService processingservice;

    // constructor injection of mandatory dependencies
    public EventProcessor(ProcessingService processingService) {
        this.processingService = processingService;
    }

    // onEvents is called when events are received on this partition of the Event Hub. 
    @Override
    public void onEvents(PartitionContext context, Iterable<EventData> events) throws Exception
    {
        //....
    }
}

自动装配不适用于事件中心示例

2 个答案: