Spring SFTP出站网关：如何在Java Config中关闭GET后的会话？

Question

I have written a piece of code which uses Spring SFTP Outbound gateway and performs a GET operation. The whole configuration is in JAVA (no XML). I have made a caching session factory which allows a maximum of 10 sessions. Due to which after multiple GET request when it exceeds 10, GET request start failing.

I read the docs and it was written to close the session after operation but i'm unable to figure out as to how to close this session in JAVA Configuration?

@org.springframework.integration.annotation.MessagingGateway
public interface FileOperationGateway {
    @Gateway(requestChannel = "sftpChannelDownload")
    InputStream downloadFromSftp(Message<Boolean> message);

}



@Bean
public SessionFactory<LsEntry> sftpSessionFactory() {
    DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory(true);
    factory.setHost(SFTP_HOST);
    factory.setPort(SFTP_PORT);
    factory.setUser(SFTP_USERNAME);
    factory.setPassword(SFTP_PASSWORD);
    factory.setAllowUnknownKeys(true);
    return new CachingSessionFactory<LsEntry>(factory);
}

/**
 * Bean for Caching the session 
 * 
 */

@Bean
@Autowired
public CachingSessionFactory<LsEntry> cachingSessionFactory(SessionFactory<LsEntry> sftpSessionFactory) {
    CachingSessionFactory<LsEntry> cachingSessionFactory = new CachingSessionFactory<>(sftpSessionFactory, 10);
    cachingSessionFactory.setSessionWaitTimeout(SFTP_SESSION_TIMEOUT);
    return cachingSessionFactory;
}

/**
 * Bean for Remote File Template 
 * 
 * @return
 * @throws Exception 
 */

@Bean
@Autowired
public RemoteFileTemplate<LsEntry> remoteFileTemplateDesigner(CachingSessionFactory<LsEntry> csf) throws Exception {
    ExpressionParser expressionParser = new SpelExpressionParser();
    Expression expression = expressionParser.parseExpression("'" + SFTP_LOCATION + "'");
    SftpRemoteFileTemplate rft = new SftpRemoteFileTemplate(csf);
    rft.setRemoteDirectoryExpression(expression);
    rft.setRemoteFileSeparator("/");
    rft.setFileNameGenerator((msg) -> {
        Timestamp timestamp = new Timestamp(System.currentTimeMillis());
        Instant instant = timestamp.toInstant();
        String fileNameFromHeader = msg.getHeaders().get(FileOperationConstants.FILE_HEADER_KEY).toString();
        String newFileName;
        if (fileNameFromHeader.lastIndexOf("/") != -1) {
            newFileName = fileNameFromHeader.substring(fileNameFromHeader.lastIndexOf("/"));
        } else if (fileNameFromHeader.lastIndexOf("\\") != -1) {
            newFileName = fileNameFromHeader.substring(fileNameFromHeader.lastIndexOf("\\"));
        } else
            newFileName = fileNameFromHeader;

        String fileNameOnly = newFileName.substring(0, newFileName.lastIndexOf("."));
        String fileType = newFileName.substring(newFileName.lastIndexOf(".") + 1);
        return (fileNameOnly + "__" + instant.toString() + "." + fileType);
    });
    rft.afterPropertiesSet();
    return rft;
}

@Bean
@Autowired
@ServiceActivator(inputChannel = "sftpChannelDownload")
public SftpOutboundGatewaySpec downloadHandler(RemoteFileTemplate<LsEntry> rft) {
    SftpOutboundGatewaySpec sogs =  Sftp.outboundGateway(rft, FileOperationConstants.FILE_DOWNLOAD_COMMAND,
            FileOperationConstants.FILE_DOWNLOAD_EXPRESSION);
    sogs.options(Option.STREAM);
    return sogs;
}

******UPDATE:******

I created a new class with @messageEndpoint and placed the closeable session code in it. I then called this handler from my service class (where i was consuming the stream)This worked:

    @MessageEndpoint
public class FileOperationCloseSessionMessageHandler {

    @ServiceActivator(inputChannel = "sftpCloseSession")
    public void closeSession(Message<Boolean> msg) throws IOException {

        Closeable closeable = new IntegrationMessageHeaderAccessor(msg).getCloseableResource();
        if (closeable != null) {
            closeable.close();
        }
    }
}

Placed this line in @MessagingGateway annotated class

@Gateway(requestChannel = "sftpCloseSession")
void closeSession(Message<InputStream> msg);

And then called the gateway method from service class:

Message<InputStream> msg = msgGateway.downloadFromSftp(message);
    InputStream is = msg.getPayload();
    msgGateway.closeSession(msg);

Answer 1

sogs.options(Option.STREAM);

When you stream the file, you are responsible for closing the session after you have finished streaming. This is explained in the documentation .

When consuming remote files as streams, the user is responsible for closing the Session after the stream is consumed. For convenience, the Session is provided in the IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE header, a convenience method is provided on the IntegrationMessageHeaderAccessor:

Closeable closeable = new IntegrationMessageHeaderAccessor(message).getCloseableResource();
if (closeable != null) {
    closeable.close();
}

Framework components such as the File Splitter and Stream Transformer will automatically close the session after the data is transferred.