Spring boot SFTP, dynamic directory in SFTP - spring-boot

Question

I tried to upload files to dynamic directory to SFTP. When I uploaded some files, the first file always uploaded to the last directory. Then after that rest file will be uploaded to the correct directory. When I did debug mode, I saw that every first file would be uploaded to temporaryDirectory which is the code already set up by spring. I don't know how to set the value of this temporaryDirectory to the right value. Please, help me to solve the problem.
Or maybe you guys have other way to upload and create proper dynamic directory. Please let me know.
Here is the code:
private String sftpRemoteDirectory = "documents/"
#MessagingGateway
public interface UploadGateway {
#Gateway(requestChannel = "toSftpChannel")
void upload(File file, #Header("dirName") String dirName);
}
#Bean
#ServiceActivator(inputChannel = "toSftpChannel")
public MessageHandler handler() {
SftpMessageHandler handler = new SftpMessageHandler(sftpSessionFactory());
SimpleDateFormat formatter = new SimpleDateFormat("yyMMdd");
String newDynamicDirectory = "E" + formatter.format(new Date())+String.format("%04d",Integer.parseInt("0001") + 1);
handler.setRemoteDirectoryExpression(new LiteralExpression(sftpRemoteDirectory + newDynamicDirectory));
handler.setFileNameGenerator(message -> {
String dirName = (String) message.getHeaders().get("dirName");
handler.setRemoteDirectoryExpression(new LiteralExpression(sftpRemoteDirectory + dirName));
handler.setAutoCreateDirectory(true);
if (message.getPayload() instanceof File) {
return (((File) message.getPayload()).getName());
} else {
throw new IllegalArgumentException("File expected as payload!");
}
});
return handler;
}

Answer 1

You are using a LiteralExpression, evaluated just once, you need an expression that's evaluated at runtime.
handler.setRemoteDirectoryExpressionString("'" + sftpRemoteDirectory/ + "'" + headers['dirName']);