问题
I am unable to get the ExpressionEvaluatingRequestHandlerAdvice class to work in Spring Integration 4.1.x. The following expression advice context XML snippet produces a conversion error stating that Spring cannot convert the property onSuccessExpression to an Expression from a String. Prior to Spring Integration 4.1.0-RELEASE the setOnSuccessExpression() method only accepted Strings, now it is overloaded to accept a String or Expression.
<sftp:outbound-channel-adapter channel="outboundChannel"
session-factory="sftpCachingSessionFactory" remote-directory="${sftp.remote.file.location.path}"
temporary-file-suffix=".tmp">
<sftp:request-handler-advice-chain>
<bean
class="org.springframework.integration.handler.advice.RequestHandlerRetryAdvice">
<property name="retryTemplate" ref="defaultRetryTemplate" />
</bean>
<bean
class="org.springframework.integration.handler.advice.ExpressionEvaluatingRequestHandlerAdvice">
<property name="onSuccessExpression" value="headers.ID" />
<property name="successChannel" ref="outboundSuccessChannel" />
</bean>
</sftp:request-handler-advice-chain>
</sftp:outbound-channel-adapter>
The following is the error being shown:
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.integration.file.config.FileWritingMessageHandlerFactoryBean#0': Cannot resolve reference to bean 'org.springframework.integration.handler.advice.ExpressionEvaluatingRequestHandlerAdvice#7d12855' while setting bean property 'adviceChain' with key [1]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.integration.handler.advice.ExpressionEvaluatingRequestHandlerAdvice#7d12855' defined in class path resource [file-transfer-service-file-endpoint-context.xml]: Initialization of bean failed; nested exception is org.springframework.beans.ConversionNotSupportedException: Failed to convert property value of type 'java.lang.String' to required type 'org.springframework.expression.Expression' for property 'onSuccessExpression'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [org.springframework.expression.Expression] for property 'onSuccessExpression': no matching editors or conversion strategy found
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:359)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveManagedList(BeanDefinitionValueResolver.java:382)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:157)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1469)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:743)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
at pmd.common.spring.SpringServiceContextLoader.main(SpringServiceContextLoader.java:63)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.integration.handler.advice.ExpressionEvaluatingRequestHandlerAdvice#7d12855' defined in class path resource [file-transfer-service-file-endpoint-context.xml]: Initialization of bean failed; nested exception is org.springframework.beans.ConversionNotSupportedException: Failed to convert property value of type 'java.lang.String' to required type 'org.springframework.expression.Expression' for property 'onSuccessExpression'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [org.springframework.expression.Expression] for property 'onSuccessExpression': no matching editors or conversion strategy found
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:547)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:351)
... 15 more
Caused by: org.springframework.beans.ConversionNotSupportedException: Failed to convert property value of type 'java.lang.String' to required type 'org.springframework.expression.Expression' for property 'onSuccessExpression'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [org.springframework.expression.Expression] for property 'onSuccessExpression': no matching editors or conversion strategy found
at org.springframework.beans.BeanWrapperImpl.convertIfNecessary(BeanWrapperImpl.java:475)
at org.springframework.beans.BeanWrapperImpl.convertForProperty(BeanWrapperImpl.java:511)
at org.springframework.beans.BeanWrapperImpl.convertForProperty(BeanWrapperImpl.java:505)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.convertForProperty(AbstractAutowireCapableBeanFactory.java:1515)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1474)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
... 21 more
Caused by: java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [org.springframework.expression.Expression] for property 'onSuccessExpression': no matching editors or conversion strategy found
at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:287)
at org.springframework.beans.BeanWrapperImpl.convertIfNecessary(BeanWrapperImpl.java:460)
... 27 more
My problem is I don't think my onSuccessExpression should be being converted there is a setter for Strings on the setOnSuccessExpression() method. Is there a fix on my part or did Spring Int create a bug?
回答1:
This is a bug; we added a second set of setters to support the DSL (so you can inject either a String or Expression).
The problem is that violates the JavaBean definition (2 setters with different parameter types) so Spring doesn't know which one to pick. We need to change the method names.
Unfortunately it's indeterminate as to which method is invoked by Spring.
In the meantime, you can try work around it with this...
<bean id="success" class="org.springframework.integration.config.ExpressionFactoryBean">
<constructor-arg value="headers.ID" />
</bean>
and...
<property name="onSuccessExpression" ref="success" />
Unfortunately, though, it's indeterminate which method is invoked; in my environment your code works because the String version of the method is selected.
So you may have to wire up the advice as a @Bean as a work-around if you are running in multiple environments.
I opened a JIRA Issue. We will get the fix in a release soon.
来源：https://stackoverflow.com/questions/27825846/cannot-convert-string-value-to-expression-for-expressionevaluatingrequesthandler