Java 构造函数SimpleCommandBus（）不可见-Axon

我正在开发

springboot+Axon

示例。我已经参考了。在本例中，当我将

axon-core

版本更新为

4.0-M2

时。当我更新Axon版本时，我发现我的主要方法是在第23行和第25行给出一些错误

依照

构造函数SimpleCommand总线（）不可见

构造函数DefaultCommandGateway（CommandBus）未定义

MessageRunner.java

public class MessagesRunner {

    public static void main(String[] args) {
        CommandBus commandBus = new SimpleCommandBus(); //Line-23

        CommandGateway commandGateway = new DefaultCommandGateway(commandBus); // Line-25

        EventStore eventStore = new EmbeddedEventStore(new InMemoryEventStorageEngine());

        EventSourcingRepository<MessagesAggregate> repository =
                new EventSourcingRepository<>(MessagesAggregate.class, eventStore);


        AggregateAnnotationCommandHandler<MessagesAggregate> messagesAggregateAggregateAnnotationCommandHandler =
                new AggregateAnnotationCommandHandler<MessagesAggregate>(MessagesAggregate.class, repository);
        messagesAggregateAggregateAnnotationCommandHandler.subscribe(commandBus);

        final AnnotationEventListenerAdapter annotationEventListenerAdapter =
                new AnnotationEventListenerAdapter(new MessagesEventHandler());
        eventStore.subscribe(eventMessages -> eventMessages.forEach(e -> {
                    try {
                        annotationEventListenerAdapter.handle(e);
                    } catch (Exception e1) {
                        throw new RuntimeException(e1);

                    }
                }

        ));

        final String itemId = UUID.randomUUID().toString();
        commandGateway.send(new CreateMessageCommand(itemId, "Hello, how is your day? :-)"));
        commandGateway.send(new MarkReadMessageCommand(itemId));
    }
}

错误-

00:27:40.704 [main] WARN org.axonframework.eventsourcing.eventstore.AbstractEventStore - Error reading snapshot for aggregate [67f0747f-a0fd-4089-9cc3-fb1fe4662cca]. Reconstructing from entire event stream.
java.lang.NullPointerException: null
    at org.axonframework.eventsourcing.eventstore.inmemory.InMemoryEventStorageEngine.readSnapshot(InMemoryEventStorageEngine.java:105)
    at org.axonframework.eventsourcing.eventstore.AbstractEventStore.readEvents(AbstractEventStore.java:80)
    at org.axonframework.eventsourcing.EventSourcingRepository.readEvents(EventSourcingRepository.java:427)
    at org.axonframework.eventsourcing.EventSourcingRepository.doLoadWithLock(EventSourcingRepository.java:404)
    at org.axonframework.eventsourcing.EventSourcingRepository.doLoadWithLock(EventSourcingRepository.java:48)
    at org.axonframework.commandhandling.model.LockingRepository.doLoad(LockingRepository.java:195)
    at org.axonframework.commandhandling.model.LockingRepository.doLoad(LockingRepository.java:50)
    at org.axonframework.commandhandling.model.AbstractRepository.lambda$load$11(AbstractRepository.java:151)
    at java.util.HashMap.computeIfAbsent(Unknown Source)
    at org.axonframework.commandhandling.model.AbstractRepository.load(AbstractRepository.java:150)
    at org.axonframework.commandhandling.AggregateAnnotationCommandHandler$AggregateCommandHandler.handle(AggregateAnnotationCommandHandler.java:219)
    at org.axonframework.commandhandling.AggregateAnnotationCommandHandler$AggregateCommandHandler.handle(AggregateAnnotationCommandHandler.java:213)
    at org.axonframework.commandhandling.AggregateAnnotationCommandHandler.handle(AggregateAnnotationCommandHandler.java:175)
    at org.axonframework.commandhandling.AggregateAnnotationCommandHandler.handle(AggregateAnnotationCommandHandler.java:44)
    at org.axonframework.messaging.DefaultInterceptorChain.proceed(DefaultInterceptorChain.java:57)
    at org.axonframework.messaging.unitofwork.DefaultUnitOfWork.executeWithResult(DefaultUnitOfWork.java:69)
    at org.axonframework.commandhandling.SimpleCommandBus.handle(SimpleCommandBus.java:176)
    at org.axonframework.commandhandling.SimpleCommandBus.doDispatch(SimpleCommandBus.java:146)
    at org.axonframework.commandhandling.SimpleCommandBus.dispatch(SimpleCommandBus.java:110)
    at org.axonframework.commandhandling.gateway.AbstractCommandGateway.send(AbstractCommandGateway.java:75)
    at org.axonframework.commandhandling.gateway.DefaultCommandGateway.send(DefaultCommandGateway.java:75)
    at org.axonframework.commandhandling.gateway.DefaultCommandGateway.send(DefaultCommandGateway.java:123)
    at com.example.demo.MessagesRunner.main(MessagesRunner.java:52)

---

在版本4.0中，我们决定为我们复杂的基础设施组件引入构建器模式。这样做的原因是，使用框架更具可读性，另一方面，在向基础架构组件添加新字段时，它为我们提供了更大的灵活性

因此，构造

SimpleCommandBus

将如下所示：

SimpleCommandBus.builder（）.build（）。您可以猜测需要为
DefaultCommandGateway
；）执行哪些操作

希望这有帮助

干杯，
米兰
这是一个完全不同的问题，然后建筑商采用@PAA的方法，因此与您创建的原始问题没有真正的联系。尽管如此，我还是建议尝试Axon 4.0，而不是里程碑式的尝试。里程碑不能完全保证没有bug。此外，MemoryEventsStorage Engine中的
通常仅用于测试场景。如果您真的想保留您的事件，我建议转到JPA、JDBC或更好的

编辑

很抱歉回复太晚，让我对您共享的代码段进行调整：

public class MessagesRunner {

    public static void main(String[] args) {
        // Adjusted - Used builder instead of constructor
        CommandBus commandBus = SimpleCommandBus.builder().build();

        // Adjusted - Used builder instead of constructor
        CommandGateway commandGateway = DefaultCommandGateway.builder()
                .commandBus(commandBus)
                .build();

        // Adjusted - Used builder instead of constructor
        EventStore eventStore = EmbeddedEventStore.builder()
                .storageEngine(new InMemoryEventStorageEngine())
                .build();

        // Adjusted - Used builder instead of constructor
        EventSourcingRepository<MessagesAggregate> repository =
                EventSourcingRepository.builder(MessagesAggregate.class)
                        .eventStore(eventStore)
                        .build();


        // Adjusted - Used builder instead of constructor
        AggregateAnnotationCommandHandler<MessagesAggregate> messagesAggregateAggregateAnnotationCommandHandler =
                AggregateAnnotationCommandHandler.<MessagesAggregate>builder()
                        .aggregateType(MessagesAggregate.class)
                        .repository(repository)
                        .build();

        messagesAggregateAggregateAnnotationCommandHandler.subscribe(commandBus);

        // Adjusted - Renamed AnnotationEventListenerAdapter to AnnotationEventHandlerAdapter
        final AnnotationEventHandlerAdapter annotationEventListenerAdapter =
                new AnnotationEventHandlerAdapter(new MessagesEventHandler());
        eventStore.subscribe(eventMessages -> eventMessages.forEach(e -> {
                    try {
                        annotationEventListenerAdapter.handle(e);
                    } catch (Exception e1) {
                        throw new RuntimeException(e1);

                    }
                }

        ));

        final String itemId = UUID.randomUUID().toString();
        commandGateway.send(new CreateMessageCommand(itemId, "Hello, how is your day? :-)"));
        commandGateway.send(new MarkReadMessageCommand(itemId));
    }
}

公共类消息运行器{
公共静态void main（字符串[]args）{
//调整-使用生成器而不是构造函数
CommandBus CommandBus=SimpleCommandBus.builder（）.build（）；
//调整-使用生成器而不是构造函数
CommandGateway CommandGateway=DefaultCommandGateway.builder（）
.commandBus（commandBus）
.build（）；
//调整-使用生成器而不是构造函数
EventStore EventStore=EmbeddedEventStore.builder（）
.storageEngine（新的InMemoryEventsStorageEngine（））
.build（）；
//调整-使用生成器而不是构造函数
EventSourcingRepository存储库=
EventSourcingRepository.builder（MessagesAggregate.class）
.eventStore（eventStore）
.build（）；
//调整-使用生成器而不是构造函数
AggregateAnnotationCommandHandler消息AggregateAnnotationCommandHandler=
AggregateNotationCommandHandler.builder（）
.aggregateType（MessagesAggregate.class）
.repository（存储库）
.build（）；
messagesaggergegateaggregateannotationcommandhandler.subscribe（commandBus）；
//调整-重命名的AnnotationEventListenerAdapter到AnnotationEventHandlerAdapter
最终注释EventHandlerAdapter注释EventListenerAdapter=
新注释EventHandlerAdapter（新消息Seventhandler（））；
订阅（eventMessages->eventMessages.forEach（e->{
试一试{
annotationEventListenerAdapter.handle（e）；
}捕获（异常e1）{
抛出新的运行时异常（e1）；
}
}
));
最后一个字符串itemId=UUID.randomUUID（）.toString（）；
send（新的CreateMessageCommand（itemId，“你好，今天好吗？”：-）））；
send（新的MarkReadMessageCommand（itemId））；
}
}

我希望这能澄清我和米兰一直试图分享的解决方案！：-）
如果没有，一定要评论
 好的，谢谢。你用上面提到的代码片段测试过了吗？@Steven-你能不能把答案粘贴得更详细一些，最好添加一段代码片段。啊，很抱歉@PAA，完全错过了你的请求。我刚刚用您的代码片段的副本更新了我的响应，在这里我调整了所有必要的位以符合Axon 4。
public class MessagesRunner {

    public static void main(String[] args) {
        // Adjusted - Used builder instead of constructor
        CommandBus commandBus = SimpleCommandBus.builder().build();

        // Adjusted - Used builder instead of constructor
        CommandGateway commandGateway = DefaultCommandGateway.builder()
                .commandBus(commandBus)
                .build();

        // Adjusted - Used builder instead of constructor
        EventStore eventStore = EmbeddedEventStore.builder()
                .storageEngine(new InMemoryEventStorageEngine())
                .build();

        // Adjusted - Used builder instead of constructor
        EventSourcingRepository<MessagesAggregate> repository =
                EventSourcingRepository.builder(MessagesAggregate.class)
                        .eventStore(eventStore)
                        .build();


        // Adjusted - Used builder instead of constructor
        AggregateAnnotationCommandHandler<MessagesAggregate> messagesAggregateAggregateAnnotationCommandHandler =
                AggregateAnnotationCommandHandler.<MessagesAggregate>builder()
                        .aggregateType(MessagesAggregate.class)
                        .repository(repository)
                        .build();

        messagesAggregateAggregateAnnotationCommandHandler.subscribe(commandBus);

        // Adjusted - Renamed AnnotationEventListenerAdapter to AnnotationEventHandlerAdapter
        final AnnotationEventHandlerAdapter annotationEventListenerAdapter =
                new AnnotationEventHandlerAdapter(new MessagesEventHandler());
        eventStore.subscribe(eventMessages -> eventMessages.forEach(e -> {
                    try {
                        annotationEventListenerAdapter.handle(e);
                    } catch (Exception e1) {
                        throw new RuntimeException(e1);

                    }
                }

        ));

        final String itemId = UUID.randomUUID().toString();
        commandGateway.send(new CreateMessageCommand(itemId, "Hello, how is your day? :-)"));
        commandGateway.send(new MarkReadMessageCommand(itemId));
    }
}