Question

我正在尝试通过教程创建基本的Axon / Spring应用程序，但是遇到类似如下的奇怪错误：NoHandlerForCommandException：没有处理程序订阅命令。看来Axon看不到@CommandHandler注释。

这是我的文件：

汇总

@Aggregate
@NoArgsConstructor
public class Account {

    @AggregateIdentifier
    private UUID accountId;
    private Double balance;

    @CommandHandler
    public Account(CreateAccountCommand command) {
        apply(new AccountCreatedEvent(command.getAccountId(), command.getName()));
    }

    @EventSourcingHandler
    protected void on(AccountCreatedEvent event) {
        this.accountId = event.getAccountId();
        this.balance = 0.0;
    } 
}

事件

@AllArgsConstructor
@Getter
public class AccountCreatedEvent {

    private UUID accountId;
    private String name;
}

命令

@Getter
public class CreateAccountCommand {

    @TargetAggregateIdentifier
    private UUID accountId;
    private String name;

    public CreateAccountCommand(UUID accountId, String name) {
        this.accountId = accountId;
        this.name = name;
    }
}

spring boot conf

@SpringBootApplication
public class App {

    @Configuration
    public static class TestConfiguration {
        @Bean
        public EventStorageEngine inMemoryEventStorageEngine() {
            return new InMemoryEventStorageEngine();
        }
    }

    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

这是我发送cmd的方式

@Component
public class AppLoader {

    @Autowired
    private CommandGateway cmdGateway;

    @PostConstruct
    public void init() {
        cmdGateway.send(new CreateAccountCommand(UUID.randomUUID(), "test"));
    }
}

我的build.gradle

buildscript {
    ext {
        springBootVersion = '2.0.5.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'

group = 'io.yourpoint.nettnews'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    testCompile group: 'org.axonframework', name: 'axon-test', version: '3.3.5'
    compile group: 'org.axonframework', name: 'axon-spring-boot-starter', version: '3.3.5'
    compile('org.springframework.boot:spring-boot-starter-webflux')
    compileOnly('org.projectlombok:lombok')
    testCompile('org.springframework.boot:spring-boot-starter-test')
    testCompile('io.projectreactor:reactor-test')
}

Answer 1

对于Axon，在CommandGateway#send()中执行@PostConstruct调用很可能早就结束了。

就目前而言，所有命令，事件和查询处理程序通常在所有bean初始化之后进行注册。将CommandGateway#send()移到REST端点后面应该给您足够的时间以确保所有处理程序都已注册。

因此，简而言之，获得NoHandlerForCommandException是一个时间问题。

我们（在AxonIQ处）看到，一旦所有处理程序都已注册，就发送某种应用程序事件是有好处的。但这是未来的事情。

希望这可以帮助您@Benjamin！

没有处理程序订阅命令。轴突3.3

1 个答案: