apollo-adminservice/src/main/java/com/ctrip/framework/apollo/adminservice/controller/AppController.java/AppController/delete
class AppController:  @DeleteMapping("/apps/{appId:.+}")
  public void delete(@PathVariable("appId") String appId, @RequestParam String operator) {
    App entity = appService.findOne(appId);
    if (entity == null) {
      throw new NotFoundException("app not found for appId " + appId);
    }
    adminService.deleteApp(entity, operator);
  }