Resgatar Blob do banco - Java

public class ServiceManageFileDownload implements AuditableControllerService {

	private AudityCore auditEngine;
	private AuditedUser user;

	public void init(CASHttpServletRequest req, HttpServletResponse resp) throws Throwable {		}

	public void service(CASHttpServletRequest req, HttpServletResponse resp) throws Throwable {
	
		TableTrRmaFile tbRmaFile = TraceUtil.getTable(TableTrRmaFile.class);	
		Long paramIdRmaFile = req.getParameterAsLong("idRmaFile", "");
		
		if (user != null) {
			
			Session session = null;
			BeanRmaFile beanRmaFile = new BeanRmaFile();
			byte [] file = null;

			try {
					session = TraceUtil.createSession();
					Select select = session.select(tbRmaFile);
					select.where(WhereConditions.equal(tbRmaFile.idFile, paramIdRmaFile));
					beanRmaFile = select.getSingleRow(tbRmaFile);
					
					file = beanRmaFile.getSlotFile();
				
			}catch (Exception e) {
				TraceCore.getInstance().getLogger().log(Logger.ERROR_DETAIL_02, e);
				e.printStackTrace();
				session.rollback();
			} finally {
				TraceUtil.close(session);
			}
			
			byte[] bytes = file;
			
			
			resp.setContentType("application/octet-stream");
			resp.setHeader("Content-disposition", "attachment; filename=\"" + beanRmaFile.getNameFile() + "\"");
			resp.getOutputStream().write(bytes);
		}
	}

	public void finish(CASHttpServletRequest req, HttpServletResponse resp) throws Throwable {}

	public Logger getLogger() {
		return TraceCore.getInstance().getLogger();
	}

	public void setAuditEngine(AudityCore auditEngine) {
		this.auditEngine = auditEngine;
	}

	public AudityCore getAuditEngine() {
		return auditEngine;
	}

	public void setUser(AuditedUser user) {
		this.user = user;
	}

	public AuditedUser getUser() {
		return user;
	}
	
}