Mule 请求回复和回滚异常策略

Question

我有一个骡子流，我在其中配置了请求回复范围。流程如下:

<flow name="RequestReplyFlow">
    <http:listener config-ref="HTTP_Listener_Configuration" path="/test" doc:name="HTTP" />
    <set-payload value="#['Sample Payload']" doc:name="Set Payload" />
    <request-reply doc:name="Request-Reply">
        <vm:outbound-endpoint exchange-pattern="one-way" path="request" doc:name="VM" />
        <vm:inbound-endpoint exchange-pattern="one-way" path="reply" doc:name="VM" />
    </request-reply>
</flow>

和

<flow name="RequestReplyFlow1">
    <vm:inbound-endpoint exchange-pattern="one-way" path="request" doc:name="VM" />
    <logger message="Executing with payload: #[payload]" level="INFO" doc:name="Logger" />
    <component class="org.ram.BusinessComponent" doc:name="Java" />
    <rollback-exception-strategy maxRedeliveryAttempts="5" doc:name="Rollback Exception Strategy">
        <logger message="Will attempt redelivery" level="INFO" doc:name="Logger" />
    </rollback-exception-strategy>
</flow>

我在 request VM 入站端点上配置了 rollback-exception-strategy。

当组件 org.ram.BusinessComponent 抛出异常时，我期望的是消息被重新传送到入站 VM 端点，但它并没有发生。为什么？

谁能解决这个问题？

Answer 1

如果您使用回滚异常策略而不是 unhandled exceptions 的默认异常策略，那么你只需要在“rollback-exception-strategy”中通过添加“vm:outbound-endpoint”和“reply”路径来手动指定重定向，请注意 maxRedeliveryAttempts 已更改为“0”，因为你的 vm 是非事务性:

<flow name="RequestReplyFlow1">
    <vm:inbound-endpoint exchange-pattern="one-way" path="request" doc:name="VM" />
    <logger message="Executing with payload: #[payload]" level="INFO" doc:name="Logger" />
    <component class="org.ram.BusinessComponent" doc:name="Java" />
    <rollback-exception-strategy maxRedeliveryAttempts="0" doc:name="Rollback Exception Strategy">
        <logger message="Will attempt redelivery" level="INFO" doc:name="Logger" />
        <vm:outbound-endpoint exchange-pattern="one-way" path="reply" doc:name="VM" />
    </rollback-exception-strategy>
</flow>

当虚拟机为 transactional 时那么值 maxRedeliveryAttempts=5 是有意义的，因为在这种情况下 Mule 会尝试重新传递消息五 (5) 次。然后，您可以通过在“on-redelivery-attempts-exceeded”子元素中添加“vm:outbound-endpoint”和“reply”路径，在“rollback-exception-strategy”中手动指定重定向:

<flow name="RequestReplyFlow1">
    <vm:inbound-endpoint exchange-pattern="one-way" path="request" doc:name="VM" />
    <logger message="Executing with payload: #[payload]" level="INFO" doc:name="Logger" />
    <component class="org.ram.BusinessComponent" doc:name="Java" />
    <rollback-exception-strategy maxRedeliveryAttempts="0" doc:name="Rollback Exception Strategy">
        <logger message="Will attempt redelivery" level="INFO" doc:name="Logger" />
        <on-redelivery-attempts-exceeded>
            <logger message="redelivery attempt exceeded" level="INFO" doc:name="Logger" />
            <vm:outbound-endpoint exchange-pattern="one-way" path="reply" doc:name="VM" />
        </on-redelivery-attempts-exceeded>
    </rollback-exception-strategy>
</flow>