我需要將圖像上傳到 FTP 服務器。因此，我創建了與 SessionFactory、MessageHandler 和 MessageGateway 的集成配置，用于將文件上傳到 FTP 服務器：@Configuration@IntegrationComponentScanpublic class FtpConfiguration {    @Bean    public SessionFactory<FTPFile> ftpSessionFactory() {        DefaultFtpSessionFactory defaultFtpSessionFactory = new DefaultFtpSessionFactory();        //setup        return new CachingSessionFactory<>(defaultFtpSessionFactory);    }    @Bean    @ServiceActivator(inputChannel = "toFtpChannel")    public MessageHandler handler() {        FtpMessageHandler handler = new FtpMessageHandler(ftpSessionFactory());        handler.setAutoCreateDirectory(true);        handler.setRemoteDirectoryExpression(new LiteralExpression(""));        handler.setFileNameGenerator(message -> (String) message.getHeaders().get("filename"));        return handler;    }    //to show you that I've tried both    /*@Bean    public IntegrationFlow ftpOutboundFlow() {        return IntegrationFlows.from("toFtpChannel")                .handle(Ftp.outboundAdapter(ftpSessionFactory(), FileExistsMode.REPLACE)                        .useTemporaryFileName(false)                        .fileNameExpression("headers['" + FileHeaders.FILENAME + "']")                        .remoteDirectory("")                ).get();    }*/    @MessagingGateway    public interface UploadGateway {        @Gateway(requestChannel = "toFtpChannel")        void upload(@Payload byte[] file, @Header("filename") String filename, @Header("path") String path);    }}成功構建應用程序。然后我試圖上傳一些文件：@AutowiredUploadGateway uploadGateway;@Overridepublic void uploadImage(byte[] scanBytes, String filename, String path) {    try {        uploadGateway.upload(scanBytes, filename, path);    } catch (Exception e) {        log.error("WRONG", e);    }}然后它說：“沒有名為'toFtpChannel'的bean可用” 我幾乎嘗試了每個教程，我做錯了什么？