java Spring集成：只从FTP服务器下载新的或更新的文件？

Question

我正在使用Spring Integration编写FTP客户端，以便从远程FTP服务器获取文件。该服务必须下载大文件，因此多次下载同一文件不是最佳选择

以下是我的配置：

@Bean
open fun ftpSessionFactory() = DefaultFtpSessionFactory().apply {
    setHost(env.getProperty(FTP_HOST))
    setPort(env.getProperty(FTP_PORT)!!.toInt())
    setUsername(env.getProperty(FTP_USER))
    setPassword(env.getProperty(FTP_PASSWORD))
}

@Bean
open fun ftpInboundFileSynchronizer() = FtpInboundFileSynchronizer(
    ftpSessionFactory()).apply {
    setDeleteRemoteFiles(false)
    setRemoteDirectory(env.getProperty(FTP_REMOTE_DIRECTORY))
    setFilter(FtpSimplePatternFileListFilter(env.getProperty(FTP_FILTER)))
}

@Bean
@InboundChannelAdapter(channel = "ftpChannel")
open fun ftpMessageSource() = FtpInboundFileSynchronizingMessageSource(
    ftpInboundFileSynchronizer()).apply {
    setLocalDirectory(File(env.getProperty(FTP_LOCAL_DIRECTORY)))
    setAutoCreateLocalDirectory(true)
    setLocalFilter(AcceptOnceFileListFilter<File>())
    maxFetchSize = 1
}

@Bean(name = [(PollerMetadata.DEFAULT_POLLER)])
open fun defaultPoller() = PollerMetadata().apply {
    maxMessagesPerPoll = 1
}

我正在下载所有与FTP_过滤器匹配的文件，还是刚刚更改

Answer 1

除了FtpSimplePatternFileListFilter之外，还需要对远程部分使用AcceptOnceFileListFilter：https://docs.spring.io/spring-integration/docs/5.0.3.RELEASE/reference/html/ftp.html#ftp-inbound：

You can also combine a pattern based filter with other filters, such as an AcceptOnceFileListFilter to avoid synchronizing files that have previously been fetched, by using a CompositeFileListFilter.