如何使用 ExpressionEvaluatingRequestHandlerAdvice 移动文件

Question

在 ExpressionEvaluatingRequestHandlerAdvice 的手册中，它清楚地表明，A typical use case for this advice might be with an <ftp:outbound-channel-adapter/>, perhaps to move the file to one directory if the transfer was successful, or to another directory if it fails。

但我无法弄清楚将有效负载从当前目录移动到另一个目录的表达式。

这个例子只是删除或重命名文件：

<bean class="org.springframework.integration.handler.advice.ExpressionEvaluatingRequestHandlerAdvice">
    <property name="onSuccessExpression" value="payload.delete()" />
    <property name="successChannel" ref="afterSuccessDeleteChannel" />
    <property name="onFailureExpression" value="payload.renameTo(new java.io.File(payload.absolutePath + '.failed.to.send'))" />
    <property name="failureChannel" ref="afterFailRenameChannel" />
</bean>

如何做到这一点？

编辑

按照 Gary 的建议，这是新的尝试：

设法将表达式更改为"T(java.nio.file.Files).move(payload.path, new java.io.File(new java.io.File('sent'), payload.name).path, T(java.nio.file.StandardCopyOption).REPLACE_EXISTING)"， 但仍然收到错误Method move(java.lang.String,java.lang.String,java.nio.file.Standar‌​dCopyOption) cannot be found on java.nio.file.Files type

代码是，

@Bean
    @ServiceActivator(inputChannel = "toSftpChannel", adviceChain = "expressionAdvice")
    public MessageHandler uploadHandler() {
        SftpMessageHandler handler = new SftpMessageHandler(sftpSessionFactory());
        handler.setRemoteDirectoryExpression(new LiteralExpression(outRemoteDirectory));
        handler.setFileNameGenerator(new FileNameGenerator() {

            @Override
            public String generateFileName(Message<?> message) {
                if (message.getPayload() instanceof File) {
                    return ((File) message.getPayload()).getName();
                } else {
                    throw new IllegalArgumentException("File expected as payload.");
                }
            }

        });
        return handler;
    }

    @MessagingGateway()
    public interface UploadGateway {

        @Gateway(requestChannel = "toSftpChannel")
        void upload(File file);

    }

@Bean
    public String onUploadSuccessExpression() {
        return "T(java.nio.file.Files).move(payload.path, new java.io.File(new java.io.File('sent'), payload.name).path, T(java.nio.file.StandardCopyOption).REPLACE_EXISTING)";
    }

@Bean
    public String onUploadFailedExpression() {
        return "payload";
    }

@Bean
    public Advice expressionAdvice() {
        ExpressionEvaluatingRequestHandlerAdvice expressionEvaluatingRequestHandlerAdvice = new ExpressionEvaluatingRequestHandlerAdvice();
        expressionEvaluatingRequestHandlerAdvice.setOnSuccessExpressionString(onUploadSuccessExpression());
        expressionEvaluatingRequestHandlerAdvice.setSuccessChannelName("uploadSuccessChannel");
        expressionEvaluatingRequestHandlerAdvice.setOnFailureExpressionString(onUploadFailedExpression());
        expressionEvaluatingRequestHandlerAdvice.setFailureChannelName("uploadFailedChannel");
        expressionEvaluatingRequestHandlerAdvice.setTrapException(true);
        expressionEvaluatingRequestHandlerAdvice.setPropagateEvaluationFailures(true);
        return expressionEvaluatingRequestHandlerAdvice;
    }

调用来自UploadGateway 的upload 方法。

堆栈跟踪是，

"main@1" prio=5 tid=0x1 nid=NA runnable
  java.lang.Thread.State: RUNNABLE
      at org.springframework.integration.handler.advice.ExpressionEvaluatingRequestHandlerAdvice.evaluateSuccessExpression(ExpressionEvaluatingRequestHandlerAdvice.java:241)
      at org.springframework.integration.handler.advice.ExpressionEvaluatingRequestHandlerAdvice.doInvoke(ExpressionEvaluatingRequestHandlerAdvice.java:214)
      at org.springframework.integration.handler.advice.AbstractRequestHandlerAdvice.invoke(AbstractRequestHandlerAdvice.java:70)
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
      at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
      at com.sun.proxy.$Proxy81.handleRequestMessage(Unknown Source:-1)
      at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.doInvokeAdvisedRequestHandler(AbstractReplyProducingMessageHandler.java:127)
      at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:112)
      at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:127)
      at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:116)
      at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:148)
      at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:121)
      at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:89)
      at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:423)
      at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:373)
      at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:115)
      at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:45)
      at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:105)
      at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:143)
      at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:135)
      at org.springframework.integration.gateway.MessagingGatewaySupport.send(MessagingGatewaySupport.java:392)
      at org.springframework.integration.gateway.GatewayProxyFactoryBean.invokeGatewayMethod(GatewayProxyFactoryBean.java:481)
      at org.springframework.integration.gateway.GatewayProxyFactoryBean.doInvoke(GatewayProxyFactoryBean.java:433)
      at org.springframework.integration.gateway.GatewayProxyFactoryBean.invoke(GatewayProxyFactoryBean.java:424)
      at org.springframework.integration.gateway.GatewayCompletableFutureProxyFactoryBean.invoke(GatewayCompletableFutureProxyFactoryBean.java:65)
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
      at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
      at com.sun.proxy.$Proxy87.upload(Unknown Source:-1)

Answer 1

如果新目录与旧目录在同一磁盘上，则在“onSuccessExpression”中，只需使用payload.renameTo(...)，类似于示例在onFailureExpression 中的使用方式。

`payload.renameTo(new java.io.File(new File('newDir'), payload.name))`

使用有效负载的名称创建一个文件到目录newDir（必须存在）。

如果您是 JDK 7 或更高版本，请使用...

T(java.nio.file.Files).move(payload.path, new java.io.File(new File('newDir'), payload.name).path)

...改为。

这将处理新目录位于不同磁盘上的情况（简单的File.renameTo() 不会）。

如果您仍在使用 JDK 6 并且新目录可能在不同的磁盘上，您将需要使用 onSuccessExpression=payload 并向 successChannel 订阅服务激活器来操作文件本身，可能使用 Spring 的 FileCopyUtils .