Question

我收到错误`不允许空相关。也许CorrelationStrategy失败了吗？

这个论坛主题似乎用下面的内容来解决它，但是这种方法对我不起作用，http://forum.spring.io/forum/spring-projects/integration/102054-aggregator-correlation-strategy-failing。

我的理解是inbound-streaming-channel-adapter将FILE_NAME作为标题值，我想加入。

    <int-ftp:inbound-streaming-channel-adapter
    auto-startup="true" id="ftpListener" channel="ftpChannel"
    session-factory="ftpSessionFactory" remote-directory="/export/home/udyj"
    filename-pattern="test1.txt">
    <integration:poller fixed-rate="5000"
        max-messages-per-poll="-1" />
</int-ftp:inbound-streaming-channel-adapter>

<int-ftp:inbound-streaming-channel-adapter
    auto-startup="true" id="ftpListener2" channel="ftpChannel"
    session-factory="ftpSessionFactory" remote-directory="/export/home/udyj"
    filename-pattern="test2.txt">
    <integration:poller fixed-rate="5000"
        max-messages-per-poll="-1" />
</int-ftp:inbound-streaming-channel-adapter>

<bean id="correlationStrategy"
    class="org.springframework.integration.aggregator.HeaderAttributeCorrelationStrategy">
    <constructor-arg value="FILE_NAME.substring(0,3)" />
</bean>
<integration:aggregator id="nuggetAggregator"
    input-channel="ftpChannel" output-channel="sendMQDistributionChannel"
    correlation-strategy="correlationStrategy">
</integration:aggregator>

Answer 1

看，你说HeaderAttributeCorrelationStrategy，肯定期望得到一个标题名称。但同时你将标题名称指定为FILE_NAME.substring(0,3)，它看起来更像一个表达式。你得到null因为实际上没有这样的标题。

如果要评估表达式，请考虑改为使用ExpressionEvaluatingCorrelationStrategy：

<bean id="correlationStrategy"
    class="org.springframework.integration.aggregator.ExpressionEvaluatingCorrelationStrategy">
    <constructor-arg value="headers.file_name.substring(0,3)" />
</bean>

Spring Integration Null相关不允许。也许CorrelationStrategy失败了吗？

1 个答案: