Question

使用Spring FTP Integration和Annotation配置，我从FTP服务器下载了文件。下载后仍然我们的应用程序触发连接服务器并找到任何新添加的文件，如果添加任何文件将从服务器下载。但我不需要维持FTP服务器会话活动并在第一次连接或第一次下载后断开服务器。

代码：

public class FtpServices {

    @Bean(name="ftpSessionFactory")
    public DefaultFtpSessionFactory ftpSessionFactory() {
        System.out.println("session");

        DefaultFtpSessionFactory sf = new DefaultFtpSessionFactory();
        sf.setHost("localhost");
        sf.setPort(21);
        sf.setUsername("user");
        sf.setPassword("password");

        return sf;
    }

    @Bean
    public FtpInboundFileSynchronizer ftpInboundFileSynchronizer() {
        System.out.println("2");
        FtpInboundFileSynchronizer fileSynchronizer = new FtpInboundFileSynchronizer(ftpSessionFactory());
        fileSynchronizer.setDeleteRemoteFiles(false);
        fileSynchronizer.afterPropertiesSet();
        fileSynchronizer.setRemoteDirectory("/test/");
       // fileSynchronizer.setFilter(new FtpSimplePatternFileListFilter("*.docx"));
        fileSynchronizer.setFilter(filter);
        return fileSynchronizer;
    }

    @Bean()
    @InboundChannelAdapter(value="ftpChannel", poller = @Poller(fixedDelay = "50", maxMessagesPerPoll = "1"))
    public FtpInboundFileSynchronizingMessageSource ftpMessageSource() {
        System.out.println(3);
        FtpInboundFileSynchronizingMessageSource source =
                new FtpInboundFileSynchronizingMessageSource(ftpInboundFileSynchronizer());
        source.setLocalDirectory(new File("D:/Test-downloaded/"));
        //source.stop();
        return source;
    }

    @Bean
    @ServiceActivator(inputChannel = "ftpChannel", requiresReply="false")
    public MessageHandler handler() {
        System.out.println(4);
        MessageHandler handler =  new MessageHandler() {

            @Override
            public void handleMessage(Message<?> message) throws MessagingException {
                System.out.println(message.getPayload()+" @ServiceActivator");
                System.out.println(" Message Header :"+message.getHeaders());
            }
        };
        return handler;
    }

    @Bean(name = PollerMetadata.DEFAULT_POLLER)
    public PollerMetadata defaultPoller() {

        PollerMetadata pollerMetadata = new PollerMetadata();
        pollerMetadata.setTrigger(triggerOnlyOnce());
        return pollerMetadata;
    }

}

并且我还覆盖了AbtractFTPSessionFactory.java以测试FTP服务器连接和断开连接过程。

protected void postProcessClientAfterConnect(T t) throws IOException {
    System.out.println("After connect");
}

protected void postProcessClientBeforeConnect(T client) throws IOException {
    System.out.println("Before connect");
}

控制台：

    INFO : org.springframework.context.support.DefaultLifecycleProcessor - Starting beans in phase -2147483648
    INFO : org.springframework.context.support.DefaultLifecycleProcessor - Starting beans in phase 0
    Before connect
    After connect
    D:\Test-downloaded\demo 1.txt @ServiceActivator
     Message Header :{id=e4a1fd7f-0bbf-9692-f70f-b0ac68b4dec4, timestamp=1477317086272}
    D:\Test-downloaded\demo.txt @ServiceActivator
     Message Header :{id=9115ee92-12b4-bf1f-d592-9c13bf7a27fa, timestamp=1477317086324}
    Before connect
    After connect
    Before connect
    After connect
    Before connect
    After connect
    Before connect
    After connect
    Before connect
    After connect
    Before connect
    After connect

感谢。

Answer 1

这实际上是任何@InboundChannelAdapter的目的：定期轮询目标系统以获取新数据。

为此，我们有时会建议OnlyOnceTrigger：

public class OnlyOnceTrigger implements Trigger {

    private final AtomicBoolean done = new AtomicBoolean();

    @Override
    public Date nextExecutionTime(TriggerContext triggerContext) {
           return !this.done.getAndSet(true) ? new Date() : null;
    }

}

但这可能对您的情况不起作用，因为源FTP目录中可能没有所需的文件。

因此，我们必须进行轮询，直到您收到所需文件，并在满足该条件时.stop()适配器。

为此，您可以使用任何下游逻辑来确定状态或考虑实施AbstractMessageSourceAdvice以注入PollerMetadata的{{1}}：http://docs.spring.io/spring-integration/reference/html/messaging-channels-section.html#conditional-pollers

文件下载后如何断开FTP服务器连接？

1 个答案: