更新：问题似乎是我正在使用两次的id，或者换句话说，就是我要用于productinventory实体的product实体的id。一旦我为产品库存实体生成新的ID，它似乎就可以正常工作。但是我想两者都具有相同的ID，因为它们是同一产品。

我有2个服务：

ProductManagementService（使用产品详细信息保存一个Product实体）

1.）为了保存产品实体，我实现了一个EventHandler，它侦听ProductCreatedEvent并将产品保存到mysql数据库中。

ProductInventoryService（将具有产品库存量的ProductInventory实体保存到ProductManagementService中定义的特定productId）

2.）为了保存ProductInventory实体，我还实现了一个EventHandler，它侦听ProductInventoryCreatedEvent并将产品保存到mysql数据库中。

我想做的事：

在ProductManagementService中创建新产品时，我想在此后直接在ProductInventoryService中创建一个ProductInventory实体，并将其保存到我的msql表中。新的ProductInventory实体应具有与Product实体相同的ID 。

为此，我创建了一个Saga，该Saga列出了ProductCreatedEvent并发送了一个新的CreateProductInventoryCommand。一旦CreateProductInventoryCommand触发一个ProductInventoryCreatedEvent，如2.）中所述的EventHandler应该捕获它。除非不是。

保存的唯一东西是产品实体，因此总而言之：

1.）有效，2.）无效。确实创建了ProductInventory Aggregate，但由于未触发连接到EventHandler的保存过程，因此未保存它。

我也收到异常，但是应用程序不会崩溃： Command 'com.myApplication.apicore.command.CreateProductInventoryCommand' resulted in org.axonframework.commandhandling.CommandExecutionException(OUT_OF_RANGE: [AXONIQ-2000] Invalid sequence number 0 for aggregate 3cd71e21-3720-403b-9182-130d61760117, expected 1)

我的传奇：

@Saga
@ProcessingGroup("ProductCreationSaga")
public class ProductCreationSaga {

    @Autowired
    private transient CommandGateway commandGateway;

    @StartSaga
    @SagaEventHandler(associationProperty = "productId")
    public void handle(ProductCreatedEvent event) {
        System.out.println("ProductCreationSaga, SagaEventHandler, ProductCreatedEvent");

        String productInventoryId = event.productId;
        SagaLifecycle.associateWith("productInventoryId", productInventoryId);
    //takes ID from product entity and sets all 3 stock attributes to zero
        commandGateway.send(new CreateProductInventoryCommand(productInventoryId, 0, 0, 0));
    }

    @SagaEventHandler(associationProperty = "productInventoryId")
    public void handle(ProductInventoryCreatedEvent event) {
        System.out.println("ProductCreationSaga, SagaEventHandler, ProductInventoryCreatedEvent");

        SagaLifecycle.end();
    }

}

可按预期工作并保存产品实体的EventHandler：

@Component
public class ProductPersistenceService {

    @Autowired
    private ProductEntityRepository productRepository;

    //works as intended
    @EventHandler
    void on(ProductCreatedEvent event) {
        System.out.println("ProductPersistenceService, EventHandler, ProductCreatedEvent");
        ProductEntity entity = new ProductEntity(event.productId, event.productName, event.productDescription, event.productPrice);
        productRepository.save(entity);

    }

    @EventHandler
    void on(ProductNameChangedEvent event) {
        System.out.println("ProductPersistenceService, EventHandler, ProductNameChangedEvent");
        ProductEntity existingEntity = productRepository.findById(event.productId).get();

        ProductEntity entity = new ProductEntity(event.productId, event.productName, existingEntity.getProductDescription(), existingEntity.getProductPrice());
        productRepository.save(entity);

    }
}

应该保存ProductInventory实体的EventHandler，但不能：

@Component
public class ProductInventoryPersistenceService {

    @Autowired
    private ProductInventoryEntityRepository productInventoryRepository;

    //doesn't work
    @EventHandler
    void on(ProductInventoryCreatedEvent event) {
        System.out.println("ProductInventoryPersistenceService, EventHandler, ProductInventoryCreatedEvent");
        ProductInventoryEntity entity = new ProductInventoryEntity(event.productInventoryId, event.physicalStock, event.reservedStock, event.availableStock);
        System.out.println(entity.toString());

        productInventoryRepository.save(entity);

    }

}

产品汇总：

@Aggregate
public class Product {

    @AggregateIdentifier
    private String productId;

    private String productName;

    private String productDescription;

    private double productPrice;

    public Product() {
    }

    @CommandHandler
    public Product(CreateProductCommand command) {
        System.out.println("Product, CommandHandler, CreateProductCommand");
        AggregateLifecycle.apply(new ProductCreatedEvent(command.productId, command.productName, command.productDescription, command.productPrice));
    }

    @EventSourcingHandler
    protected void on(ProductCreatedEvent event) {
        System.out.println("Product, EventSourcingHandler, ProductCreatedEvent");

        this.productId = event.productId;
        this.productName = event.productName;
        this.productDescription = event.productDescription;
        this.productPrice = event.productPrice;
    }

}

产品库存汇总

@Aggregate
public class ProductInventory {

    @AggregateIdentifier
    private String productInventoryId;

    private int physicalStock;

    private int reservedStock;

    private int availableStock;

    public ProductInventory() {
    }


    @CommandHandler
    public ProductInventory(CreateProductInventoryCommand command) {
        System.out.println("ProductInventory, CommandHandler, CreateProductInventoryCommand");
        AggregateLifecycle.apply(new ProductInventoryCreatedEvent(command.productInventoryId, command.physicalStock, command.reservedStock, command.availableStock));
    }

    @EventSourcingHandler
    protected void on(ProductInventoryCreatedEvent event) {
        System.out.println("ProductInventory, EventSourcingHandler, ProductInventoryCreatedEvent");

        this.productInventoryId = event.productInventoryId;
        this.physicalStock = event.physicalStock;
        this.reservedStock = event.reservedStock;
        this.availableStock = event.availableStock;
    }

}