java - 如何在发送到 DLQ 之前处理消息

Question

我正在使用以下服务器端重新传递配置

 <plugins>
    <redeliveryPlugin fallbackToDeadLetter="true" sendToDlqIfMaxRetriesExceeded="true">
        <redeliveryPolicyMap>
            <redeliveryPolicyMap>
                <redeliveryPolicyEntries>
                    <redeliveryPolicy 
                        queue = "com.api.RequestQueue.v1"
                        maximumRedeliveries="20"                        
                        initialRedeliveryDelay="60000" 
                        redeliveryDelay="60000" />

                    <redeliveryPolicy 
                        queue = "com.api.RequestQueue.v2"
                        maximumRedeliveries="10"                        
                        initialRedeliveryDelay="30000" 
                        redeliveryDelay="30000" />
                    <redeliveryPolicy 
                        queue = "com.api.ResponseQueue.v1"
                        maximumRedeliveries="3"                         
                        initialRedeliveryDelay="34000" 
                        redeliveryDelay="34000" />                          
                </redeliveryPolicyEntries>
            </redeliveryPolicyMap>
        </redeliveryPolicyMap>
    </redeliveryPlugin>
</plugins>

如何设置自定义端点来在重试后和发送到 DLQ 之前处理失败的消息？我确实引用了以下链接，但找不到任何有关服务器端或 redeliveryPlugin 配置的内容

1. dead-letter-channel

2. logging-camel-exceptions-and-sending-to-the-dead-letter-channel

Answer 1

如果您使用蓝图或 spring，那么可以轻松完成，如下所示:

<!-- Redelivery Policy -->
<bean class="org.apache.camel.processor.RedeliveryPolicy" id="redeliveryPolicyConfig">
    <property name="5" />
    <property name="redeliveryDelay" value="5000" />
    <property name="logRetryAttempted" value="true" />
</bean>

<!-- Error Handler -->
<bean class="org.apache.camel.builder.DeadLetterChannelBuilder" id="errorHandler">
    <property name="deadLetterUri" value="direct:error" />
    <property name="useOriginalMessage" value="true" />
    <property name="redeliveryPolicy" ref="redeliveryPolicyConfig" />
</bean>

然后在“deadLetterUri”属性中添加错误处理程序指向的路由，如下所示:

<!-- Perform custom logic and send to DLQ -->
<route id="myDLQ-route">
    <from uri="direct:error" />
    <!-- Maybe some logic here, logging perhaps? -->
    <to uri="activemq:queue:myDLQ" />
</route>