Gibt es eine Möglichkeit, leere Payload-Nachricht mit Spring Integration Gateway zu senden?

Question

Ich versuche, RPC mit Spring-Integration AMQP zu machen, ich habe eine Methode, die keine Argumente innerhalb meines Gateways, aber die Nachricht wird nicht an meine Börse gesendet, wenn ich es anrufe.

@MessagingGateway 
public interface StatusGateway { 
    boolean getStatus(); 
} 

Hier meine integrations context.xml

<rabbit:connection-factory id="rabbitConnectionFactory" 
    host="172.17.0.2" virtual-host="/myvhost" 
    username="myuser" password="mypasswd" /> 

<rabbit:template id="default" connection-factory="rabbitConnectionFactory" /> 
<rabbit:topic-exchange name="slr-input" auto-declare="false" /> 

<int:gateway id="statusGateway" 
    service-interface="com.example.StatusGateway" 
    default-request-channel="requestChannel" 
    default-reply-channel="replyChannel" /> 

<int:channel id="requestChannel" /> 
<int:channel id="replyChannel" /> 

<int-amqp:outbound-gateway id="statusRequestGateway" 
    amqp-template="default" 
    exchange-name="slr-input" 
    routing-key="operation.status" 
    request-channel="requestChannel" 
    reply-channel="replyChannel" 
    lazy-connect="true" /> 

Und wenn ich die getStatus Methode, die ich die folgende Ausnahme erhalten rufen

java.lang.IllegalStateException: Failed to execute CommandLineRunner 
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:803) [spring-boot-1.3.6.RELEASE.jar:1.3.6.RELEASE] 
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:784) [spring-boot-1.3.6.RELEASE.jar:1.3.6.RELEASE] 
    at org.springframework.boot.SpringApplication.afterRefresh(SpringApplication.java:771) [spring-boot-1.3.6.RELEASE.jar:1.3.6.RELEASE] 
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.6.RELEASE.jar:1.3.6.RELEASE] 
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1185) [spring-boot-1.3.6.RELEASE.jar:1.3.6.RELEASE] 
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1174) [spring-boot-1.3.6.RELEASE.jar:1.3.6.RELEASE] 
    at com.example.AmqpTestClientApplication.main(AmqpTestClientApplication.java:14) [classes/:na] 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91] 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91] 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91] 
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91] 
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144) [idea_rt.jar:na] 
Caused by: java.lang.IllegalStateException: receive is not supported, because no pollable reply channel has been configured 
    at org.springframework.util.Assert.state(Assert.java:392) ~[spring-core-4.2.7.RELEASE.jar:4.2.7.RELEASE] 
    at org.springframework.integration.gateway.MessagingGatewaySupport.receive(MessagingGatewaySupport.java:380) ~[spring-integration-core-4.2.8.RELEASE.jar:na] 
    at org.springframework.integration.gateway.GatewayProxyFactoryBean.invokeGatewayMethod(GatewayProxyFactoryBean.java:416) ~[spring-integration-core-4.2.8.RELEASE.jar:na] 
    at org.springframework.integration.gateway.GatewayProxyFactoryBean.doInvoke(GatewayProxyFactoryBean.java:382) ~[spring-integration-core-4.2.8.RELEASE.jar:na] 
    at org.springframework.integration.gateway.GatewayProxyFactoryBean.invoke(GatewayProxyFactoryBean.java:373) ~[spring-integration-core-4.2.8.RELEASE.jar:na] 
    at org.springframework.integration.gateway.GatewayCompletableFutureProxyFactoryBean.invoke(GatewayCompletableFutureProxyFactoryBean.java:64) ~[spring-integration-core-4.2.8.RELEASE.jar:na] 
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.2.7.RELEASE.jar:4.2.7.RELEASE] 
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208) ~[spring-aop-4.2.7.RELEASE.jar:4.2.7.RELEASE] 
    at com.sun.proxy.$Proxy44.getStatus(Unknown Source) ~[na:na] 
    at com.example.AmqpTestClientApplication.lambda$commandLineRunner$0(AmqpTestClientApplication.java:20) [classes/:na] 
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:800) [spring-boot-1.3.6.RELEASE.jar:1.3.6.RELEASE] 

Weiß jemand, wie eine Anfrage zu machen, ohne das Senden eine nicht leere Nachricht?

Answer 1

Eine Gateway-Methode ohne Argumente ist standardmäßig eine Empfangsoperation. siehe Messaging Gateway: Invoking No-Argument Methods.

Sie können etwas wie das Hinzufügen default-payload-expression="''" zum Gateway (ein leerer String) verwenden.