Spring SPEL:setRemoteDirecotoryExpressionの問題

2020-02-14 spring-integration spring-el

Java SpringのSPEL言語を使用して、SFTPサーバーのリモートディレクトリを設定しようとしています。基本的に、リモートディレクトリパスとして2つの文字列を一緒に追加しようとしていますが、何らかの理由でまだ理解しようとしていますが、機能しません。 ここに私がやることがあります:

ExpressionParser EXPRESSION_PARSER = new SpelExpressionParser();
Expression exp = EXPRESSION_PARSER.parseExpression("headers['path']"); //which contains the 2nd part of the path to my dir
String fullFilePath = this.remoteDir; //which has the 1st part of the path to my directory
SftpMessageHandler handler = new SftpMessageHandler(sftpSessionFactory());
handler.setRemoteDirectoryExpressionString(this.remoteDir.concat("/").concat(exp.getValue().toString()));
handler.setAutoCreateDirectory(true);

exp.getValue()メソッドには何か問題があるようです。その行がコメントされていない場合、次の例外が発生するためです。

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'SFTPConfig' defined in file [/Users/psdev/PrediSurge/backend/file-service/target/classes/com/predisurge/planopsuite/microservices/fileservice/sftp/SFTPConfig.class]: Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'handler' defined in class path resource [com/predisurge/planopsuite/microservices/fileservice/sftp/SFTPConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.messaging.MessageHandler]: Circular reference involving containing bean 'SFTPConfig' - consider declaring the factory method as static for independence from its containing instance. Factory method 'handler' threw exception; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1007E: Property or field 'headers' cannot be found on null
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:584) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:846) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863) ~[spring-context-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546) ~[spring-context-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142) ~[spring-boot-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) [spring-boot-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) [spring-boot-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) [spring-boot-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) [spring-boot-2.1.2.RELEASE.jar:2.1.2.RELEASE]
    at com.predisurge.planopsuite.microservices.fileservice.FileServiceApplication.main(FileServiceApplication.java:26) [classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_241]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_241]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_241]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.1.2.RELEASE.jar:2.1.2.RELEASE]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'handler' defined in class path resource [com/predisurge/planopsuite/microservices/fileservice/sftp/SFTPConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.messaging.MessageHandler]: Circular reference involving containing bean 'SFTPConfig' - consider declaring the factory method as static for independence from its containing instance. Factory method 'handler' threw exception; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1007E: Property or field 'headers' cannot be found on null
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:627) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:456) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1288) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1127) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.integration.config.annotation.AbstractMethodAnnotationPostProcessor.resolveTargetBeanFromMethodWithBeanAnnotation(AbstractMethodAnnotationPostProcessor.java:464) ~[spring-integration-core-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.integration.config.annotation.AbstractMethodAnnotationPostProcessor.postProcess(AbstractMethodAnnotationPostProcessor.java:146) ~[spring-integration-core-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.integration.config.annotation.MessagingAnnotationPostProcessor.processAnnotationTypeOnMethod(MessagingAnnotationPostProcessor.java:190) ~[spring-integration-core-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.integration.config.annotation.MessagingAnnotationPostProcessor.lambda$postProcessAfterInitialization$0(MessagingAnnotationPostProcessor.java:163) ~[spring-integration-core-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:589) ~[spring-core-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.integration.config.annotation.MessagingAnnotationPostProcessor.postProcessAfterInitialization(MessagingAnnotationPostProcessor.java:144) ~[spring-integration-core-5.1.2.RELEASE.jar:5.1.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:434) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1749) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:576) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    ... 20 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.messaging.MessageHandler]: Circular reference involving containing bean 'SFTPConfig' - consider declaring the factory method as static for independence from its containing instance. Factory method 'handler' threw exception; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1007E: Property or field 'headers' cannot be found on null
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:622) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    ... 38 common frames omitted
Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1007E: Property or field 'headers' cannot be found on null
    at org.springframework.expression.spel.ast.PropertyOrFieldReference.readProperty(PropertyOrFieldReference.java:213) ~[spring-expression-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:104) ~[spring-expression-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:91) ~[spring-expression-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.expression.spel.ast.CompoundExpression.getValueRef(CompoundExpression.java:53) ~[spring-expression-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:89) ~[spring-expression-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:109) ~[spring-expression-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:138) ~[spring-expression-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    at com.predisurge.planopsuite.microservices.fileservice.sftp.SFTPConfig.handler(SFTPConfig.java:101) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_241]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_241]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_241]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
    ... 39 common frames omitted

私はJava Springを初めて使用するわけではありませんが、SPELを使用したことがないため、何が間違っているのかよくわかりません。 任意の助けをいただければ幸いです。

Answers

EL式「headers ['path']」は、おそらくキー「path」を含むマップを指します。デフォルトでは、スプリング式パーサーには外部変数に関する情報がありません。 StandardEvaluationContextのインスタンスを作成し、変数「ヘッダー」を登録して、式の値を取得するときにこのコンテキストを使用する必要があります。

ExpressionParser EXPRESSION_PARSER = new SpelExpressionParser();

// create context and register variable "headers"
StandardEvaluationContext context = new StandardEvaluationContext();
context.setVariable("headers",headers);

Expression exp = EXPRESSION_PARSER.parseExpression("headers['path']"); 
String fullFilePath = this.remoteDir; 
SftpMessageHandler handler = new SftpMessageHandler(sftpSessionFactory());

// use context, when getting evaluated value
 handler.setRemoteDirectoryExpressionString(this.remoteDir.concat("/").concat(exp.getValue(context).toString()));
        handler.setAutoCreateDirectory(true);

以下は、スプリングELで変数を使用するためのリファレンスです。

handler.setRemoteDirectoryExpressionString(this.remoteDir.concat("/").concat(exp.getValue().toString()));

式は実行時にメッセージに対して評価する必要があります。設定時に式を評価します。

使用する

"'" + this.remoteDir + "/' + headers['path']"

そのため、 headers['path']はハンドラーに送信されたメッセージに対して評価されます。

Related