有没有办法使用 DSL 分叉 Spring IntegrationFlow？答案

【问题标题】：Is there a way to fork the Spring IntegrationFlow using DSL?有没有办法使用 DSL 分叉 Spring IntegrationFlow？
【发布时间】：2020-08-26 20:33:33
【问题描述】：

我想做这样的事情，其中网关有效负载是一个字符串，并且 serviceA 和 serviceB 都返回列表。

    final IntegrationFlow flowA = flow -> flow
            .handle(serviceA) 
            .handle((payload, headers) -> payload); // List<Object>

    final IntegrationFlow flowB = flow -> flow
            .handle(serviceB) 
            .handle((payload, headers) -> payload); // List<Object>


    return IntegrationFlows
            .from(myGateway) // String payload
            .forkAndMerge(flowA, flowB, executor)
            .handle((payload, headers) -> payload)
            .get();

是否可以将流分成两部分然后收集结果？大多数拆分器和聚合器示例都涉及拆分列表。

【问题讨论】：

我知道我可以创建一个自定义组件来执行此操作，但我更喜欢使用框架

标签： spring-integration spring-integration-dsl

【解决方案1】：

查看.scatterGather() 变体。

Main docs for the ScatterGatherer here.

编辑

例子：

@SpringBootApplication
public class So63605348Application {

    private static final Logger log = LoggerFactory.getLogger(So63605348Application.class);

    public static void main(String[] args) {
        SpringApplication.run(So63605348Application.class, args);
    }

    @Bean
    IntegrationFlow flow(TaskExecutor exec) {
        return IntegrationFlows.from(() -> "foo", e -> e.poller(Pollers.fixedDelay(5000)))
                .scatterGather(s -> s.applySequence(true)
                        .recipientFlow(subFlow -> subFlow.channel(c -> c.executor(exec))
                                .<String>handle((p, h) -> {
                                    log.info(p.toString());
                                    return p.toUpperCase();
                                }))
                        .recipientFlow(subFlow -> subFlow.channel(c -> c.executor(exec))
                                .<String>handle((p, h) -> {
                                    log.info(p.toString());
                                    return p + p;
                                })))
                .handle(System.out::println)
                .get();
    }

    @Bean
    public TaskExecutor exec() {
        ThreadPoolTaskExecutor exec = new ThreadPoolTaskExecutor();
        exec.setCorePoolSize(2);
        return exec;
    }

}

结果

2020-08-26 17:33:56.769  INFO 50829 --- [         exec-1] com.example.demo.So63605348Application   : foo
2020-08-26 17:33:56.769  INFO 50829 --- [         exec-2] com.example.demo.So63605348Application   : foo
GenericMessage [payload=[foofoo, FOO], headers=...

EDIT2

如果您不想嵌套子流，可以将它们分解出来...

@Bean
IntegrationFlow flow(TaskExecutor exec) {
    return IntegrationFlows.from(() -> "foo", e -> e.poller(Pollers.fixedDelay(5000)))
            .scatterGather(s -> s.applySequence(true)
                    .recipientFlow(flow2())
                    .recipientFlow(flow3()))
            .handle(System.out::println)
            .get();
}

@Bean
IntegrationFlow flow2() {
    return f -> f
        .<String>handle((p, h) -> {
            log.info(p.toString());
            return p + p;
        });
}

@Bean
IntegrationFlow flow3() {
    return f -> f
        .<String>handle((p, h) -> {
            log.info(p.toString());
            return p.toUpperCase();
        });
}

或者您可以使用 pub/sub 频道变体...

@Bean
IntegrationFlow flow() {
    return IntegrationFlows.from(() -> "foo", e -> e.poller(Pollers.fixedDelay(5000)))
            .scatterGather(pubSub())
            .handle(System.out::println)
            .get();
}

@Bean
PublishSubscribeChannel  pubSub() {
    PublishSubscribeChannel pubSub = new PublishSubscribeChannel(exec());
    pubSub.setApplySequence(true);
    return pubSub;
}

@Bean
IntegrationFlow flow2() {
    return IntegrationFlows.from("pubSub")
        .<String>handle((p, h) -> {
            log.info(p.toString());
            return p + p;
        })
        .get();
}

@Bean
IntegrationFlow flow3() {
    return IntegrationFlows.from("pubSub")
        .<String>handle((p, h) -> {
            log.info(p.toString());
            return p.toUpperCase();
        })
        .get();
}

【讨论】：

我加了一个例子。