Spring Integration Dispatcher 没有频道订阅者答案

【问题标题】：Spring Integration Dispatcher has no subscribers for channelSpring Integration Dispatcher 没有频道订阅者
【发布时间】：2017-05-05 12:08:48
【问题描述】：

我正在使用 Spring 集成及其对 MQTT 的支持；我看到了 spring 集成文档，我的简单测试用例是在 MQTT 主题上发布消息。 Spring 文档位于：http://docs.spring.io/spring-integration/reference/html/mqtt.html#_configuring_with_java_configuration_15

我正在使用这些版本：

春天 4.3.4
spring 集成 4.3.5

我构建了这个简单的配置类：

@Configuration
@IntegrationComponentScan
public class CommunicationServerApplication
{
    @Bean
    public MqttPahoClientFactory mqttClientFactory()
    {
        DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();
        factory.setServerURIs(mqttServerUris);
        if (StringUtils.hasText(mqttUsername) && StringUtils.hasText(mqttPassword))
        {

            factory.setUserName(mqttUsername);
            factory.setPassword(mqttPassword);
        }
        factory.setConnectionTimeout(mqttConnectionTimeout);
        factory.setKeepAliveInterval(mqttKeepAliveInterval);
        factory.setPersistence(new MqttDefaultFilePersistence(mqttPersistenceFileDirectory));
        return factory;
    }

    @Bean
    @ServiceActivator(inputChannel = "mqttOutboundChannel", autoStartup="true")
    public MessageHandler mqttOutbound()
    {
        String clientId = mqttClientId;
        if( !StringUtils.hasText(clientId) )
        {
            clientId = UUID.randomUUID().toString();
        }
        MqttPahoMessageHandler messageHandler = new MqttPahoMessageHandler(clientId, mqttClientFactory());
        messageHandler.setAsync(true);
        messageHandler.setDefaultTopic(mqttTopic);
        if( mqttQos >= 0 && mqttQos <=2 )
        {

            messageHandler.setDefaultQos(mqttQos);
        }
        return messageHandler;
    }

    @Bean
    public MessageChannel mqttOutboundChannel()
    {
        DirectChannel dc = new DirectChannel();
        return dc;
    }

    @MessagingGateway(defaultRequestChannel = "mqttOutboundChannel")
    public interface MqttMsgproducer
    {

        void sendToMqtt(String data);
    }
}

然后我使用了这个简单的测试用例：

@ContextConfiguration(value ={ "classpath:app-ctx.xml"})
@RunWith(SpringJUnit4ClassRunner.class)
public class SimpleMqttTestSuite
{
    private static final Logger logger = LoggerFactory.getLogger(SimpleMqttTestSuite.class.getName());
    @Autowired
    private MqttMsgproducer sender;
    @Test
    public void startServerTest()
    {
        try
        {
            sender.sendToMqtt("Hello");
        }
        catch (Exception e)
        {
            logger.error("Error", e);
        }
    }
}

我的 app-ctx.xml 是：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:oxm="http://www.springframework.org/schema/oxm"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd  
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd 
    http://www.springframework.org/schema/oxm http://www.springframework.org/schema/oxm/spring-oxm.xsd 
    http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="it.olegna.test.integration" />
    <context:property-placeholder location="classpath:configuration.properties"
        order="0" ignore-resource-not-found="true" ignore-unresolvable="true" />    
</beans>

执行简单的测试，我遇到了这个错误：

2016-12-20 10:46:33,889 49967 [nioEventLoopGroup-3-1] ERROR - Errore 
org.springframework.messaging.MessageDeliveryException: Dispatcher has no subscribers for channel 'org.springframework.context.support.GenericApplicationContext@2e6a8155.mqttOutboundChannel'.; nested exception is org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers
    at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:81) ~[spring-integration-core-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:423) ~[spring-integration-core-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:373) ~[spring-integration-core-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:115) ~[spring-messaging-4.3.4.RELEASE.jar:4.3.4.RELEASE]
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:45) ~[spring-messaging-4.3.4.RELEASE.jar:4.3.4.RELEASE]
    at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:105) ~[spring-messaging-4.3.4.RELEASE.jar:4.3.4.RELEASE]
    at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:143) ~[spring-messaging-4.3.4.RELEASE.jar:4.3.4.RELEASE]
    at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:135) ~[spring-messaging-4.3.4.RELEASE.jar:4.3.4.RELEASE]
    at org.springframework.integration.gateway.MessagingGatewaySupport.send(MessagingGatewaySupport.java:375) ~[spring-integration-core-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.integration.gateway.GatewayProxyFactoryBean.invokeGatewayMethod(GatewayProxyFactoryBean.java:477) ~[spring-integration-core-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.integration.gateway.GatewayProxyFactoryBean.doInvoke(GatewayProxyFactoryBean.java:429) ~[spring-integration-core-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.integration.gateway.GatewayProxyFactoryBean.invoke(GatewayProxyFactoryBean.java:420) ~[spring-integration-core-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.integration.gateway.GatewayCompletableFutureProxyFactoryBean.invoke(GatewayCompletableFutureProxyFactoryBean.java:65) ~[spring-integration-core-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.4.RELEASE.jar:4.3.4.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) ~[spring-aop-4.3.4.RELEASE.jar:4.3.4.RELEASE]

我无法弄清楚我在配置中缺少什么。有人可以给我小费吗？

谢谢

安杰洛

【问题讨论】：

不是您问题的答案，但可能对一些在标题中搜索错误消息的人有用：我在遵循 Spring 5 文档中的 MQTT 示例时遇到了类似的错误。我必须用adapter.setOutputChannelName("mqttInputChannel") 替换adapter.setOutputChannel(mqttInputChannel()) 才能使其工作。

标签： spring spring-integration

【解决方案1】：

您的解决方案不正确 - 您不得在频道 bean 定义中订阅。我相信您的问题是您在课堂上缺少@EnableIntegration。

【讨论】：

我希望得到一些澄清 :) 我按照你的建议进行了尝试，它有效
@EnableIntegration 修复与在通道 bean 定义中订阅无关
订阅侧 bean 定义的最佳方法是什么？
从用户代码订阅频道是不寻常的（罕见的）；通常，框架会在消费者启动时自动订阅消费者（通常是自动的）。
@GaryRussell EnableIntegration Annotation 是否需要转到定义我的频道的位置？我有时仍然收到调度程序错误以及link 这个错误，在我看来它们是相关的。

【解决方案2】：

我解决了我的问题

这与我建立了 Channel 但现在处理程序已被订阅的事实有关

在我的应用程序类中，我执行了以下操作：

@Bean
public MessageChannel mqttOutboundChannel()
{
    DirectChannel dc = new DirectChannel();
    dc.subscribe(mqttOutbound());
    return dc;
}

正如您现在所看到的，我手动将订阅 bean mqttOutbound（消息处理程序）添加到 Channel

通过这种方式，一切正常

希望对你有帮助

安杰洛

加里·罗素回答后更新

按照 Gary Russell 的建议，我没有订阅频道

我添加了注解@EnableIntegration

所以我的应用程序类现在如下：

@Configuration
@IntegrationComponentScan
@EnableIntegration
public class CommunicationServerApplication
{
    @Bean
    public MqttPahoClientFactory mqttClientFactory()
    {
        DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();
        factory.setServerURIs(mqttServerUris);
        if (StringUtils.hasText(mqttUsername) && StringUtils.hasText(mqttPassword))
        {

            factory.setUserName(mqttUsername);
            factory.setPassword(mqttPassword);
        }
        factory.setConnectionTimeout(mqttConnectionTimeout);
        factory.setKeepAliveInterval(mqttKeepAliveInterval);
        factory.setPersistence(new MqttDefaultFilePersistence(mqttPersistenceFileDirectory));
        return factory;
    }

    @Bean
    @ServiceActivator(inputChannel = "mqttOutboundChannel", autoStartup="true")
    public MessageHandler mqttOutbound()
    {
        String clientId = mqttClientId;
        if( !StringUtils.hasText(clientId) )
        {
            clientId = UUID.randomUUID().toString();
        }
        MqttPahoMessageHandler messageHandler = new MqttPahoMessageHandler(clientId, mqttClientFactory());
        messageHandler.setAsync(true);
        messageHandler.setDefaultTopic(mqttTopic);
        if( mqttQos >= 0 && mqttQos <=2 )
        {

            messageHandler.setDefaultQos(mqttQos);
        }
        return messageHandler;
    }

    @Bean
    public MessageChannel mqttOutboundChannel()
    {
        DirectChannel dc = new DirectChannel();
        return dc;
    }

    @MessagingGateway(defaultRequestChannel = "mqttOutboundChannel")
    public interface MqttMsgproducer
    {

        void sendToMqtt(String data);
    }
}

【讨论】：