spring-integration-kafka xml多个主题不起作用

Question

My project works just fine if there's just one topic defined in XML file. When I'm trying to add another topic, it just can't produce any message of either topic. My XML file is like below:

<int-kafka:producer-configurations>
    <int-kafka:producer-configuration broker-list="127.0.0.1:9092"
                   topic="test"         
                   key-class-type="java.lang.String"
                   value-class-type="java.lang.String"
                   value-encoder="encoder"
                   key-encoder="encoder"
                   compression-type="none"
                />
    <int-kafka:producer-configuration broker-list="127.0.0.1:9092"
                   topic="test2"            
                   key-class-type="java.lang.String"
                   value-class-type="java.lang.String"
                   value-encoder="encoder"
                   key-encoder="encoder"
                   compression-type="none"
                />
</int-kafka:producer-configurations>

Anyone who knows about my problem would be great help, thanks

Answer 1

It looks like you are not providing any information as to which topic to route to.

When there is only one topic, in that situation, it will be used.

If there are more than one, you will get an exception:

throw new IllegalStateException("Could not send messages as there are multiple producer configurations " +
                "with no topic information found from the message header.");

By default, the adapter will look for the topic to route to in the kafka_topic message header.

You can also provide a topic-expression , eg topic-expression="headers['foo']" and the topic will be obtained from the foo header.