我想在spring中获取带有预授权注解的参数：

@RequestMapping(value = "/remove/{id}", method = RequestMethod.GET)
@PreAuthorize("#id != authentication.id")
public boolean remove(@PathVariable Long id) { ... }

但我有个错误：

SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/Spring_sec4] threw exception [Request processing failed; nested exception is java.lang.IllegalArgumentException: Failed to evaluate expression '#id != authentication.id'] with root cause
org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'id' cannot be found on object of type 'org.springframework.security.authentication.UsernamePasswordAuthenticationToken' - maybe not public?

怎样才能做到？
我使用以下代码在控制器的方法中获取当前用户：

UserApp currentUserApp = (UserApp) SecurityContextHolder.getContext().getAuthentication().getPrincipal();

然后

if ( currentUserApp.getId().equals(id) ) {
    throw new Exception("You can't remove yourself");
}