Question

让我们说我在Spring XD中有一个自定义模块（我使用Spring XD + Spring Integration + hibernate）。该模块基本上是从DB获取的东西（让我们说我使用hibernate实体存储它，所以我使用一个名为＆＃34的对象; DataFromDB＆＃34;）。 DataFromDB是一个列表，然后我从列表中获取每个元素，我想用以下内容发送它：

String payload = convertDataFromDBToJson(record);
return MessageBuilder.createMessage(payload, message.getHeaders());

问题是每次我必须发送消息时我必须返回一条消息。
所以我想循环遍历DataFromDB列表并将每个元素作为消息发送。

有没有办法发送多条消息？

编辑：

我刚刚根据试图复制场景的评论创建了一个小例子。这就是我所拥有的：

我的变压器类：

public class TransformerClass {
public Collection<Message<?>> transformerMethod(Message<?> message) {
    List<Message<?>> messages = new ArrayList<Message<?>>();
    messages.add(new GenericMessage<>("foo"));
    messages.add(new GenericMessage<>("bar"));
    return messages;
}

我的xml配置：

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:int="http://www.springframework.org/schema/integration"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration.xsd
        http://www.springframework.org/schema/tx  http://www.springframework.org/schema/tx/spring-tx.xsd">

    <tx:annotation-driven />
    <int:channel id="input" />

    <bean id="transFormerClass" class="myModule.TransformerClass">
    </bean>

    <int:transformer input-channel="input" output-channel="output" ref="transFormerClass" method="transformerMethod"/>

    <int:channel id="output"/>

</beans>

我的测试班：

    @ModuleName(value = "someModule", type = ModuleType.processor)
public class TransformerClassTest extends xDTest {
    private String streamName = "myStream";
    private String chainTest = "someModule";

    @SuppressWarnings("unchecked")
    @Test
    public void testPartnerNotification() throws IOException {

        this.chain = SingleNodeProcessingChainSupport.chain(application, streamName, chainTest);
        //Just to send something to the module as a input.
        Message<String> input = MessageBuilder.createMessage("hello world", buildHeaders());
        this.chain.send(input);
        //Receiving a Single message
        Message<String> result = (Message<String>) chain.receive(5000);
        System.out.println("Result: " + result);
    }

    private MessageHeaders buildHeaders() {
        Map<String, Object> hashMap = new HashMap<String,Object>();
        hashMap.put("test", "testing");
        MessageHeaders headers = new MessageHeaders(hashMap);
        return headers;
    }    
}

输出是：

结果：GenericMessage [payload = [GenericMessage [payload = foo，headers = {timestamp = 1475072951345，id = 7b6c79a2-db85-563e-c238-262a31141456}]，GenericMessage [payload = bar，headers = {timestamp = 1475072951345， id = 31c8ef0e-3513-b95e-3a25-4fd3550f2fea}]]，headers = {timestamp = 1475072951347，id = f90d94c4-e323-70ed-62ee-4b8bce64814d，test = testing}]

我使用的是Spring Integration 4.2.2.RELEASE。

Answer 1

如果您返回Collection<Message<?>>，则会将其作为单独的消息发送。

修改

@EnableIntegration @Configuration public class So39708474Application { @Bean public DirectChannel input() { return new DirectChannel(); } @Bean public DirectChannel output() { return new DirectChannel(); } @Bean public Foo foo() { return new Foo(); } public static class Foo { @ServiceActivator(inputChannel = "input", outputChannel = "output") public Collection<Message<?>> handle(Message<?> in) { List<Message<?>> messages = new ArrayList<Message<?>>(); messages.add(new GenericMessage<>("foo")); messages.add(new GenericMessage<>("bar")); return messages; } } }

和

@RunWith(SpringRunner.class) @ContextConfiguration(classes = So39708474Application.class) public class So39708474ApplicationTests { @Autowired private MessageChannel input; @Autowired private SubscribableChannel output; @Test public void contextLoads() { AtomicInteger count = new AtomicInteger(); this.output.subscribe(m -> { count.incrementAndGet(); System.out.println(m); }); this.input.send(new GenericMessage<>("test")); assertEquals(2, count.get()); } }

Spring：使用循环

1 个答案: