java - Spring Integration FTP 使用后删除本地文件(Spring Boot)

Question

我正在尝试编写一个程序，该程序可以通过 ftp 从一台服务器获取文件并通过 ftp 将其放置在另一台服务器上。但是，我在写入本地文件后删除本地文件时遇到问题。只要它是临时的，能够在本地保存它不是问题。我尝试将 ExpressionEvaluatingRequestHandlerAdvice 与 OnSuccessExpression 一起使用，但我无法让它实际使用该表达式。代码在这里:

@Configuration
@EnableConfigurationProperties(FTPConnectionProperties.class)
public class FTPConfiguration {

    private FTPConnectionProperties ftpConnectionProperties;

    public FTPConfiguration(FTPConnectionProperties ftpConnectionProperties) {
        this.ftpConnectionProperties = ftpConnectionProperties;
    }

    @Bean
    public SessionFactory<FTPFile> ftpInputSessionFactory() {
        DefaultFtpSessionFactory sf = new DefaultFtpSessionFactory();
        sf.setHost(ftpConnectionProperties.getInputServer());
        sf.setUsername(ftpConnectionProperties.getInputFtpUser());
        sf.setPassword(ftpConnectionProperties.getInputFtpPassword());
        return new CachingSessionFactory<>(sf);
    }

    @Bean
    public SessionFactory<FTPFile> ftpOutputSessionFactory() {
        DefaultFtpSessionFactory sf = new DefaultFtpSessionFactory();
        sf.setHost(ftpConnectionProperties.getOutputServer());
        sf.setUsername(ftpConnectionProperties.getOutputFtpUser());
        sf.setPassword(ftpConnectionProperties.getOutputFtpPassword());
        return new CachingSessionFactory<>(sf);
    }

    @Bean
    public FtpInboundFileSynchronizer ftpInboundFileSynchronizer() {
        FtpInboundFileSynchronizer fileSynchronizer = new FtpInboundFileSynchronizer(ftpInputSessionFactory());
        fileSynchronizer.setDeleteRemoteFiles(true);
        fileSynchronizer.setRemoteDirectory(ftpConnectionProperties.getInputDirectory());
        fileSynchronizer.setFilter(new FtpSimplePatternFileListFilter("*.TIF"));
        return fileSynchronizer;
    }

    @Bean
    @InboundChannelAdapter(channel = "input", poller = @Poller(fixedDelay = "5000"))
    public MessageSource<File> ftpMessageSource() {
        FtpInboundFileSynchronizingMessageSource source = new FtpInboundFileSynchronizingMessageSource(ftpInboundFileSynchronizer());
        source.setLocalDirectory(new File("ftp-inbound"));
        source.setAutoCreateLocalDirectory(true);
        source.setLocalFilter(new FileSystemPersistentAcceptOnceFileListFilter(new SimpleMetadataStore(), ""));
        return source;
    }

    @Bean
    @ServiceActivator(inputChannel = "input")
    public MessageHandler handler() {
        FtpMessageHandler handler = new FtpMessageHandler(ftpOutputSessionFactory());
        handler.setRemoteDirectoryExpression(new LiteralExpression(ftpConnectionProperties.getOutputDirectory()));
        handler.setFileNameGenerator(message -> {
            if (message.getPayload() instanceof File) {
                return ((File) message.getPayload()).getName();
            } else {
                throw new IllegalArgumentException("File expected as payload.");
            }
        });
        return handler;
    }

}

它完全按照预期处理远程文件，从源中删除远程文件并放入输出中，但在使用后不会删除本地文件。

Answer 1

我建议您将该 input channel 设为 PublishSubscribeChannel 并添加一个简单的订阅者:

@Bean
public PublishSubscribeChannel input() {
    return new PublishSubscribeChannel();
}


@Bean
@ServiceActivator(inputChannel = "input")
public MessageHandler handler() {
    ...
}


@Bean
@ServiceActivator(inputChannel = "input")
public MessageHandler deleteLocalFileService() {
    return m ->  ((File) message.getPayload()).delete();
}

这样，带有 File 负载的相同消息将首先发送到您的 FtpMessageHandler，然后才发送到这个新的 deleteLocalFileService用于根据负载删除本地文件。