java Spring Integration：具有默认输出通道的基于内容的路由器？
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Spring Integration: Content based router with default output channel?
提问by otto.poellath
I'd like use Spring Integration to implement a content based router that uses a default output channel if the expression value doesn't match any of the mappings. Here's my bean definition:
如果表达式值与任何映射都不匹配，我想使用 Spring Integration 来实现基于内容的路由器，该路由器使用默认输出通道。这是我的 bean 定义：
<int:router input-channel="channel_in" default-output-channel="channel_default" expression="payload.name">
<int:mapping value="foo" channel="channel_one" />
<int:mapping value="bar" channel="channel_two" />
However, it seems the default output channel is never used. If the expression evaluates to e.g. 'baz', the router seems to be looking for a channel named 'baz', instead of routing to the 'channel_default' channel:
但是，似乎从未使用过默认输出通道。如果表达式的计算结果为“baz”，则路由器似乎正在寻找名为“baz”的通道，而不是路由到“channel_default”通道：
org.springframework.integration.MessagingException: failed to resolve channel name 'baz'
Caused by: org.springframework.integration.support.channel.ChannelResolutionException:
failed to look up MessageChannel bean with name 'baz'
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException:
No bean named 'baz' is defined
Is what I want at all possible using the XML namespace, or do I need to code up my own implementation?
使用 XML 命名空间完全可以实现我想要的，还是需要编写自己的实现？
回答by otto.poellath
Turns out that all I had to to to make this work was to set the router's ignore-channel-name-resolution-failures attribute to false:
事实证明，要完成这项工作，我所要做的就是将路由器的 ignore-channel-name-resolution-failures 属性设置为 false：
<int:router input-channel="channel_in" default-output-channel="channel_default"
expression="payload.name" ignore-channel-name-resolution-failures="true">
<int:mapping value="foo" channel="channel_one" />
<int:mapping value="bar" channel="channel_two" />
</int:router>
I thought I had tried that before, but I seems I didn't.
我以为我以前试过，但我似乎没有。
回答by m190
As mentioned in reference docs:
如参考文档中所述：
As of Spring Integration 2.1, router parameters have been more standardized across all router implementations. Consequently, a few minor changes may break older Spring Integration based applications.
Since Spring Integration 2.1, the
ignore-channel-name-resolution-failuresattribute is removed in favor of consolidating its behavior with theresolution-requiredattribute. Also, the resolution-required attribute now defaults totrue.Prior to these changes, the
resolution-requiredattribute defaulted tofalse, causing messages to be silently dropped when no channel was resolved and nodefault-output-channelwas set. The new behavior requires at least one resolved channel and, by default, throws aMessageDeliveryExceptionif no channel was determined (or an attempt to send was not successful).If you do desire to drop messages silently, you can set
default-output-channel="nullChannel".
从 Spring Integration 2.1 开始，路由器参数在所有路由器实现中都更加标准化。因此，一些小的更改可能会破坏旧的基于 Spring Integration 的应用程序。
从 Spring Integration 2.1 开始，该
ignore-channel-name-resolution-failures属性已被删除，以支持将其行为与该resolution-required属性合并。此外，分辨率要求的属性现在默认为true。在这些更改之前，该
resolution-required属性默认为false，这会导致在未解析任何通道且未default-output-channel设置任何通道时静默丢弃消息。新行为至少需要一个已解析的通道，并且默认情况下，MessageDeliveryException如果未确定通道（或尝试发送未成功），则抛出 。如果您确实希望静默删除消息，则可以设置
default-output-channel="nullChannel".
And if you are using Java DSL, the configuration may looks like this:
如果您使用的是 Java DSL，则配置可能如下所示：
IntegrationFlows.from("process")
.<JobExecution, String>route(m -> m.getExitStatus().getExitCode(),
m -> m.channelMapping(ExitStatus.COMPLETED.getExitCode(), "succeed")
.defaultOutputChannel("failed")
.resolutionRequired(false))
.get();
回答by Ramneek Handa
if you are using for Spring boot 2.1.2.RELEASE
如果您使用的是 Spring Boot 2.1.2.RELEASE
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-integration</artifactId>
</dependency>
then resolution-required="false"is required instead of ignore-channel-name-resolution-failures.
然后需要 resolution-required="false"而不是 ignore-channel-name-resolution-failures。
<int:router input-channel="channel_in" default-output-channel="channel_default"
expression="payload.name" resolution-required="false">
<int:mapping value="foo" channel="channel_one" />
<int:mapping value="bar" channel="channel_two" />
</int:router>
