Spring Mqtt 集成：出站主题问题

Question

您好，我正在尝试使用 spring 集成来接收 MQTT 消息，处理它们并发布到另一个主题。

这里是 integration.xml:

   <int-mqtt:outbound-channel-adapter id="mqtt-publish"
    client-id="spring-foo-1"
    client-factory="clientFactory"
    auto-startup="true"
    url="tcp://localhost:1883"
    default-qos="0"
    default-retained="true"
    default-topic="tweets/akki" />

   <int-mqtt:message-driven-channel-adapter id="oneTopicAdapter"
    client-id="spring-foo-2"
    client-factory="clientFactory"
    auto-startup="true"
    url="tcp://localhost:1883"
    topics="mqtt/publish"
    />

    <int:service-activator input-channel="oneTopicAdapter" method="logMessages" ref="mqttLogger" output-channel="mqtt-publish"></int:service-activator>

    <bean id="mqttLogger" class="hello.mqttReceiver" />

和mqttReceiver.java：

package hello;
public class mqttReceiver {
   public String logMessages(String a){
       String processed_data = a; //TODO Process Data
       return processed_data;
   }
}

以下是我面临的问题：

processed_data 被路由到 mqtt/publish 而不是 mqtt/akki
processed_data不是发表过多次

Answer 1

这是正确的，因为 AbstractMqttMessageHandler 首先查看 headers:

String topic = (String) message.getHeaders().get(MqttHeaders.TOPIC);
    Object mqttMessage = this.converter.fromMessage(message, Object.class);
    if (topic == null && this.defaultTopic == null) {
        throw new MessageHandlingException(message,
                "No '" + MqttHeaders.TOPIC + "' header and no default topic defined");
    }

当 DefaultPahoMessageConverter 在消息到达时从 MqttPahoMessageDrivenChannelAdapter 填充 MqttHeaders.TOPIC header。

在向 <int-mqtt:outbound-channel-adapter>

发送消息之前，您应该考虑使用 <int:header-filter header-names="mqtt_topic"/>

Spring Mqtt 集成：出站主题问题

Spring Mqtt integration: outbound topic issue

spring-integration

mqtt

mosquitto