更新：
如果您只是想找一个Kafka制作人的例子，那么请对您的服务进行以下更改：

@Service
@EnableBinding({Source.class})
public class KafkaWriterService {

    private final MessageChannel output;

    public KafkaWriterService(@Qualifier("output") MessageChannel output) {
        this.output = output;
    }

    public void write(String str) {
        output.send(MessageBuilder.withPayload(str).build());
    }
}
``` `@SendTo` 需要通过的消息源 `@StreamListener` . 它用于转换输入消息。
在测试程序中，没有生成任何消息。
将代码更改为以下内容，以便在测试中生成消息：

@Service
@EnableBinding({Source.class, Sink.class})
public class KafkaWriterService {

@StreamListener(Sink.INPUT)
@SendTo(Source.OUTPUT)
public String write(String str) {
    return "Transformed: " + str;
}

}

@SpringBootTest
@RunWith(SpringRunner.class)
public class KafkaWriterServiceTest {

@Autowired
private Sink sink;

@Autowired
private Source source;

@Autowired
private MessageCollector collector;

@Autowired
private KafkaWriterService service;

@Test
public void testMessages() {
    BlockingQueue<Message<?>> messages = collector.forChannel(source.output());
    sink.input().send(MessageBuilder.withPayload("Hello World!").build());

    Object payload = messages.poll().getPayload();
    System.out.println(payload);
}

}