如何利用@PreAuthorize注解自定义权限校验

@Configuration
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class WebSecurityConfig extends WebSecurityConfigurerAdapter implements WebMvcConfigurer {....}

// service取名sc是方便注解调用
@Service("sc")
@Slf4j
public class SginCheckService {

    @Autowired
    private PlatformManageService platformManageService;

    public boolean checkSgin(){
        HttpServletRequest request = UserContextHolder.getHttpServletRequest();
        String appid = request.getHeader("appid");
        String signature = request.getHeader("signature");
        String timestamp = request.getHeader("timestamp");
        //非crm管理平台
        PlatformManage platformManage = platformManageService.getOne(Wrappers.<PlatformManage>lambdaQuery().eq(PlatformManage::getSourcetype, appid));
        if (platformManage == null) {
            log.error("平台不存在:" + appid);
             //鉴权失败抛出自定义异常
            throw new SginCheckException();
        }
        //校验签名
        String secretKey = platformManage.getPrivateKey();
        MD5 md5 = new MD5();
        String lowerCase = md5.getMD5ofStr(appid + secretKey + timestamp).toLowerCase();
        if (!lowerCase.equals(signature)) {
            log.error("签名校验失败:" + "crm:" + lowerCase + "，接口:" + signature);
            //鉴权失败抛出自定义异常
            throw new SginCheckException();
        }
        //如果鉴权成功不return true 会报错.
        return true;
    }
}

public class SginCheckException extends BaseException {
    public SginCheckException() {
        super();
    }
    public SginCheckException(String message) {
        super(SystemErrorType.SIGNATURE_ERROR,message);
    }
}

@ControllerAdvice
@Slf4j
public class GlobalExceptionHandler {
	/**
     * 签名失败抛出异常处理
     *
     * @param e
     * @return
     */
    @ResponseBody
    @ResponseStatus(HttpStatus.UNAUTHORIZED)
    @ExceptionHandler(value = {SginCheckException.class})
    public Result sginCheckException(SginCheckException e) {
        return Result.fail(SystemErrorType.SIGNATURE_ERROR);
    }
}

	// 调用方法语法  @beanname.methodname() 
 	@ApiOperation(value = "会员注册", notes = "会员注册", httpMethod = "POST")
    @PostMapping("/register")
    @PreAuthorize("@sc.checkSgin()")
    public Result register(@RequestBody @Valid MemberRegisterParam memberRegisterParam, HttpServletRequest request) {
        log.error("会员注册:" + memberRegisterParam);
        return memberService.register(memberRegisterParam, request);
    }