java集成smartBi导出资源失败，clientId该如何获取

PortalService portalService = new PortalService(conn);
String clientId = portalService.openEntirePage("I4028be92018727b427b4784b0187a1b315a63e19");
File file = new File(System.getProperty("user.dir") + File.separator + "test.xlsx");
FileOutputStream fos = new FileOutputStream(file);
portalService.doExport(clientId, "xlsx", 1024, fos);

这是个啥？