如何在 spring 集成 DSL 中为通道设置多个消息处理程序?

问题描述：

我编写了我的第一个 spring 集成应用程序，它从 spring RSS 读取数据并将其记录到控制台:

I wrote my first spring integration application which reads data from spring RSS and logs it into console:

@Configuration
@EnableIntegration
@IntegrationComponentScan
public class DslConfig {

    @Bean
    public IntegrationFlow feedFlow() throws MalformedURLException {
        return IntegrationFlows.from(inBoundFeedDataAdapter(), configurer -> configurer.poller(Pollers.fixedDelay(1000)))
                .channel(newsChannel())
                .transform(source -> {
                    SyndEntry e = ((SyndEntry) source);
                    return e.getTitle() + " " + e.getLink();
                })
                .handle(messageHandler())
                .get();
    }

    @Bean
    public FeedEntryMessageSourceSpec inBoundFeedDataAdapter() throws MalformedURLException {
        return Feed.inboundAdapter(new URL("https://spring.io/blog.atom"), "some_key");
    }

    @Bean
    public MessageChannel newsChannel() {
        return new DirectChannel();
    }

    @Bean
    public MessageHandler messageHandler() {
        return System.out::println;
    }
}

但我不知道如何添加一个额外的处理程序来将结果写入文件.

But I have no idea how can I add one additional handler for writing result into file.

我怎样才能实现它?

其他问题:

元数据键是什么意思?

答

有一个 publishSubscribeChannel() 放置在流程中，你可以在那里添加 subscribe()对于几个子流.他们每个人都将获得相同的消息进行处理.如果您还在配置中添加了 Executor，则该过程将并行发生:

There is a publishSubscribeChannel() to place in the flow and there you can add subscribe() for several sub-flows. Each of them is going to get the same message to process. If you also add an Executor to the configuration, the process is going to happen in parallel:

.publishSubscribeChannel(s -> s
                        .applySequence(true)
                        .subscribe(f -> f
                                .handle((p, h) -> "Hello"))
                        .subscribe(f -> f
                                .handle((p, h) -> "World!"))
                );

See more info in Docs: https://docs.spring.io/spring-integration/docs/5.2.0.BUILD-SNAPSHOT/reference/html/dsl.html#java-dsl-subflows

如何在 spring 集成 DSL 中为通道设置多个消息处理程序?

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