我的用例很简单。我想处理因系统无法访问而导致的异常，根据配置的重试策略执行重试，在满足重试阈值时发送电子邮件，并将自定义响应返回给调用者。
我面临的挑战是，我不能同时发送电子邮件并将回复返回给来电者。由于我最初使用int-mail:outbound-channel-adapter，我希望这种行为，因为这是一个单向组件：
<int:chain input-channel="defaultErrorChannel">
<int:service-activator id="mailMessageActivator" expression="@mailHandler.process(payload)" />
<int-mail:outbound-channel-adapter mail-sender="mailSender" />
</int:chain>
但是，如果我在int-amqp:outbound-gateway前面引入int-mail:outbound-channel-adapter（请参阅下面的Error Handling配置），我希望能够调用int:service-activator来构造并向调用者返回一个响应。
我是否以错误的方式思考这个问题？我看到其他人有一个similar question仍未得到答复。我提到的两个配置都发送电子邮件，但总是阻止调用者在超时时没有收到响应。
以下是我配置的相关部分：
网关
<int:gateway id="customerGateway" service-interface="com.uscs.crm.integration.CustomerGateway"
default-request-channel="syncCustomers" default-reply-channel="replySyncCustomers" default-reply-timeout="30000">
</int:gateway>
<int:object-to-json-transformer input-channel="syncCustomers" output-channel="outboundRequestChannel" />
<int-http:outbound-gateway request-channel="outboundRequestChannel" reply-channel="replySyncCustomers"
url="http://voorhees148.uscold.com:9595/web/customerSync/createCustomer"
http-method="POST"
rest-template="restTemplate"
expected-response-type="com.uscs.crm.model.CustSyncResponseVO"
mapped-request-headers="Authorization, HTTP_REQUEST_HEADERS">
<int-http:request-handler-advice-chain>
<ref bean="retryWithBackoffAdviceSession" />
</int-http:request-handler-advice-chain>
</int-http:outbound-gateway>
错误处理
<int:channel id="defaultErrorChannel"/>
<int:channel id="errorResponses"/>
<!--
ExponentialBackOffPolicy.multipler is applied to wait time over each retry attempt
with a ExponentialBackOffPolicy.maximum configured.
-->
<bean id="retryWithBackoffAdviceSession" class="org.springframework.integration.handler.advice.RequestHandlerRetryAdvice">
<property name="retryTemplate">
<bean class="org.springframework.retry.support.RetryTemplate">
<property name="backOffPolicy">
<bean class="org.springframework.retry.backoff.ExponentialBackOffPolicy">
<property name="initialInterval" value="2000" />
<property name="multiplier" value="2" />
<property name="maxInterval" value="30000"/>
</bean>
</property>
<property name="retryPolicy">
<bean class="org.springframework.retry.policy.SimpleRetryPolicy">
<property name="maxAttempts" value="3"/>
</bean>
</property>
</bean>
</property>
<property name="recoveryCallback">
<bean class="org.springframework.integration.handler.advice.ErrorMessageSendingRecoverer">
<constructor-arg ref="defaultErrorChannel"/>
</bean>
</property>
</bean>
<bean id="custSyncResponseHandler" class="com.uscs.crm.integration.handler.CustSyncResponseHandler"></bean>
<int:chain input-channel="defaultErrorChannel" output-channel="replySyncCustomers">
<int:service-activator id="mailMessageActivator" expression="@mailHandler.process(payload)" />
<int:header-enricher>
<int:header name="ERROR_ID" expression="T(java.lang.System).currentTimeMillis()"/>
</int:header-enricher>
<int-amqp:outbound-gateway
exchange-name="error-responses-exchange"
routing-key-expression="'error.response.'+headers.ERROR_ID"
amqp-template="amqpTemplate" />
<!-- Will this service-activator return a response to the caller (int:gateway) using channel `replySyncCustomers`? -->
<int:service-activator id="custSyncResponseActivator" expression="@custSyncResponseHandler.process(payload)" />
</int:chain>
<int-amqp:inbound-gateway queue-names="error-responses" request-channel="errorResponses"
connection-factory="rabbitConnectionFactory" acknowledge-mode="AUTO" />
<int-mail:outbound-channel-adapter channel="errorResponses" mail-sender="mailSender" />
<!-- (Outbound Channel Adapter/Gateway) rabbit exchanges, queues, and bindings used by this app -->
<rabbit:topic-exchange name="error-responses-exchange" auto-delete="false" durable="true">
<rabbit:bindings>
<rabbit:binding queue="error-responses" pattern="error.response.*"/>
</rabbit:bindings>
</rabbit:topic-exchange>
<rabbit:queue name="error-responses" auto-delete="false" durable="true"/>
解决方案 ：我能够在@Artem的帮助下完成此工作。以下是我所做的更改。
服务激活器实施（处理ErrorMessage）
关键是返回重建Message的行，其中包含ErrorMessage的所有标题信息。
@Override
public Message<CustSyncResponseVO> process(Message<MessagingException> errorMessage) {
MessagingException errorException = errorMessage.getPayload();
CustSyncResponseVO custSyncResponse = new CustSyncResponseVO();
custSyncResponse.setResponseMessage(ExceptionUtils
.convertToString(errorMessage.getPayload()));
return MessageBuilder.withPayload(custSyncResponse)
.copyHeaders(errorMessage.getHeaders())
.copyHeadersIfAbsent(errorException.getFailedMessage().getHeaders()).build();
}
服务激活器配置
使用SpEL引用#root上下文来检索ErrorMessage而不是默认值MessagingException（payload）并将其传递给process <bean id="custSyncResponseHandler" class="com.uscs.crm.integration.handler.CustSyncResponseHandler" />
<int:chain id="errorGatewayResponseChain" input-channel="defaultErrorChannel" output-channel="replySyncCustomers">
<int:service-activator id="custSyncResponseActivator" expression="@custSyncResponseHandler.process(#root)" />
</int:chain>
POJO上的方法。
Battery History:
-9m49s747ms 100 64020043 status=discharging health=good plug=none temp
=317 volt=4145 +wifi +wifi_running +wake_lock +sensor brightness=light signal_st
rength=great
-9m49s507ms 100 24020043 -wake_lock
-9m46s968ms 100 24020043
-9m43s749ms 100 24020043 volt=4107
-9m38s472ms 100 240a0043 status=full plug=ac temp=318 +plugged
Per-PID Stats:
PID 1184 wake time: +1s315ms
PID 5096 wake time: +1s18ms
PID 1184 wake time: +29ms
PID 1945 wake time: +188ms
PID 2125 wake time: +42ms
PID 3757 wake time: +25ms
PID 1184 wake time: +11ms
PID 1184 wake time: +12ms
PID 4008 wake time: +90ms
PID 7441 wake time: +28ms
Statistics since last unplugged:
Time on battery: 11s 275ms (1.9%) realtime, 11s 275ms (1.9%) uptime
Total run time: 9m 49s 748ms realtime, 9m 49s 748ms uptime,
Screen on: 0ms (0.0%), Input events: 0, Active phone call: 0ms (0.0%)
Screen brightnesses: No activity
Mobile total received: 0B, Total sent: 0B
Wi-Fi total received: 0B, Total sent: 0B
Total full wakelock time: 0ms , Total partial wakelock time: 1s 151ms
Signal levels: great 11s 275ms (100.0%) 0x
Signal scanning time: 0ms
Radio types: none 11s 275ms (100.0%) 0x
Radio data uptime when unplugged: 0 ms
Wifi on: 11s 275ms (100.0%), Wifi running: 11s 275ms (100.0%), Bluetooth on: 0
ms (0.0%)
Device is currently plugged into power
Last discharge cycle start level: 100
Last discharge cycle end level: 100
Amount discharged while screen on: 0
Amount discharged while screen off: 0
1000:
User activity: 6 other, 1 touch
Wake lock SCREEN_FROZEN: 187ms partial (1 times) realtime
Wake lock StartingDockService: 832ms partial (1 times) realtime
Wake lock DockObserver: 10ms partial (1 times) realtime
Wake lock AlarmManager: 56ms partial (1 times) realtime
TOTAL wake: 1s 85ms partial realtime
Sensor 21: 11s 275ms realtime (0 times)
Sensor 33: 11s 275ms realtime (0 times)
Proc mm-pp-daemon:
CPU: 0ms usr + 180ms krn ; 0ms fg
Proc charger_monitor:
CPU: 0ms usr + 20ms krn ; 0ms fg
Proc com.honeywell.licenseservice:
CPU: 0ms usr + 10ms krn ; 0ms fg
Proc com.qualcomm.qualcommsettings:
CPU: 0ms usr + 10ms krn ; 0ms fg
Proc surfaceflinger:
CPU: 70ms usr + 100ms krn ; 0ms fg
Proc com.android.settings:
CPU: 10ms usr + 0ms krn ; 0ms fg
Proc system_server:
CPU: 540ms usr + 370ms krn ; 0ms fg
Proc com.hsm.android.counters:
CPU: 20ms usr + 0ms krn ; 0ms fg
Proc com.honeywell.tools.honsystemservice:
CPU: 10ms usr + 0ms krn ; 0ms fg
Apk com.android.settings:
Service com.android.settings.bluetooth.DockService:
Created for: 1s 8ms uptime
Starts: 1, launches: 1
答案 0 :(得分：1)
我认为没有理由在最后发送电子邮件时引入AMQP中间件复杂性。
只有<publish-subscribe-channel id="defaultErrorChannel">才能将端点作为订阅者。
第一个是单向电子邮件发送<chain>，第二个是custSyncResponseActivator来回复您<int-http:outbound-gateway>的内容。
您可以在Spring Integration Reference Manual中找到有关此问题的更多信息。