java - Axon 夹具注入(inject)在 @CommandHandler 注解的方法中失败(构造函数除外)

Question

我目前正在使用 Axon 4.2，并且我有一个聚合(Customer)，它在其 @CommandHandlers 中使用注入(inject)的服务(CustomerService) 方法。

下面显示了它的简化版本(但对于本示例仍然有效)。

@Aggregate
public class Customer {

  @AggregateIdentifier
  private Long id;
  private String name;
  private String address;

  @CommandHandler
  public Customer(CreateCommand command, CustomerService customerService) {
    log.debug( customerService.doSomething(command.getId()));
    AggregateLifecycle.apply(new CreatedEvent(command.getId(), command.getName()));
  }

  @CommandHandler
  public void on(UpdateCommand command, CustomerService customerService){
    log.debug( customerService.doSomething(command.getId()));
    AggregateLifecycle.apply( new UpdatedEvent(command.getId(),command.getAddress()));
  }

  @EventSourcingHandler
  public void on(CreatedEvent event){
    this.id = event.getId();
    this.name = event.getName();
  }

  @EventSourcingHandler
  public void on(UpdatedEvent event){
      this.address = event.getAddress();
  }
}

这是相应的测试:

@RunWith(MockitoJUnitRunner.class)
public class CustomerTest {

  @Mock
  private CustomerService customerService;
  private FixtureConfiguration<Customer> fixture;

  @Before
  public void setUp() {
    fixture = new AggregateTestFixture<>(Customer.class);
    fixture.registerInjectableResource(customerService);
  }

  @Test
  public void testCreation(){

    final Long id = 1L;
    final String name = "Elmo";
    when(customerService.doSomething(id)).thenReturn("called");

    fixture.givenNoPriorActivity()
            .when(new CreateCommand(id, name))
            .expectEvents(new CreatedEvent(id, name));

    verify(customerService).doSomething(id);
    verifyNoMoreInteractions(customerService);
  }

  @Test
  public void testUpdate(){

    final Long id = 1L;
    final String name = "Elmo";
    final String address = "Sesame street";

    when(customerService.doSomething(id)).thenReturn("called");

    fixture.givenState(() -> new Customer(id, name, null))
            .when(new UpdateCommand(id, address))
            .expectEvents(new UpdatedEvent(id, address));

    verify(customerService).doSomething(id);
    verifyNoMoreInteractions(customerService);
  }
}

代码工作正常，但测试存在问题。事实上，testCreation() 测试通过，但 testUpdate() 测试失败并出现以下错误。

org.axonframework.test.FixtureExecutionException: 
No resource of type [CustomerService] has been registered. It is required for one of the handlers being executed.

at org.axonframework.test.FixtureResourceParameterResolverFactory$FailingParameterResolver.resolveParameterValue(FixtureResourceParameterResolverFactory.java:58)
    at org.axonframework.messaging.annotation.AnnotatedMessageHandlingMember.resolveParameterValues(AnnotatedMessageHandlingMember.java:156)
    at org.axonframework.messaging.annotation.AnnotatedMessageHandlingMember.handle(AnnotatedMessageHandlingMember.java:132)
    at org.axonframework.messaging.annotation.WrappedMessageHandlingMember.handle(WrappedMessageHandlingMember.java:61)
    at org.axonframework.modelling.command.inspection.AnnotatedAggregate.handle(AnnotatedAggregate.java:427)
    at org.axonframework.modelling.command.inspection.AnnotatedAggregate.lambda$handle$3(AnnotatedAggregate.java:400)
    at org.axonframework.messaging.Scope.executeWithResult(Scope.java:111)
...

如果我删除 on UpdateCommand 方法中的 CustomerService 参数(以及相关代码)，则 testUpdate() 测试通过，因此问题似乎出在依赖注入(inject)中。

Answer 1

聚合是 DomainDrivenDesign ( https://axoniq.io/resources/domain-driven-design ) 中的重要战术模式(主要构建 block )。在 Axon 中，聚合接受业务命令，这通常会产生与业务领域相关的事件——领域事件。首先，您不应该将逻辑委托(delegate)给某些外部 CustomerService 服务。您可以在 Axon Reference guide. 上找到有关如何设计聚合的更多详细信息。此外，this chapter提供带注释的消息处理函数的所有可能参数的详尽列表。