代码如下：

public boolean checkCarInBlackListByCache(String carNumber, String projectCode, Long parkingAreaId) {
    Object o = redisUtil.get(getCarNumberCacheKey(carNumber, projectCode));
    if (Objects.isNull(o)) {
        ParkingBlackListQuery query = new ParkingBlackListQuery();
        query.setCarNumber(carNumber);
        query.setProjectCode(projectCode);
        List<ParkingBlackListBO> list = list(query);
        if (CheckUtils.isEmpty(list)) {
            return false;
        }
        ParkingBlackListBO parkingBlackListBO = list.get(0);
        redisUtil.set(getCarNumberCacheKey(carNumber, projectCode), parkingBlackListBO.getId());
        Date date = new Date();
        boolean valid = date.after(parkingBlackListBO.getEffectiveTimeBegin()) && date.before(parkingBlackListBO.getEffectiveTimeEnd());
        return valid && parkingBlackListBO.getParkingArea().contains(parkingAreaId.toString());
    }
    Long id = (Long) o;
    ParkingBlackListBO parkingBlackListBO = get(id);
    if (Objects.isNull(parkingBlackListBO)) {
        return false;
    }
    Date date = new Date();
    boolean valid = date.after(parkingBlackListBO.getEffectiveTimeBegin()) && date.before(parkingBlackListBO.getEffectiveTimeEnd());
    return valid && parkingBlackListBO.getParkingArea().contains(parkingAreaId.toString());
}

@Override
@Transactional(readOnly = true, rollbackFor = Throwable.class)
@Cacheable(value = "ParkingBlackListBOCache", key = "#id", unless = "#result == null")
public ParkingBlackListBO get(Long id) {
    if (id == null) {
        throw new RuntimeException("参数id不能为空");
    }
    // 查询数据之前的业务扩展
    getBefore(id);
    ParkingBlackListBO bo;
    try {
        // 执行数据库查询操作
        bo = getDao(id);
    } catch (Exception e) {
        throw new RuntimeException("持久化操作异常", e);
    }
    // 数据查询之后的扩展
    getAfter(bo);
    // 数据查询成功之后的扩展
    return getSuccess(bo);
}

当调用checkCarInBlackListByCache 该方法时，根据日志，发现每次还调用数据库查询。然后分析具体日志，发现调用get方法时，还是调用了数据库。判断是缓存注解没有起作用。

通过debug，跟踪源代码知道调用了缓存拦截器的方法org.springframework.cache.interceptor.CacheInterceptor#invoke

然后调用，切面注解支持方法进行具体的缓存注解处理org.springframework.cache.interceptor.CacheAspectSupport#execute(org.springframework.cache.interceptor.CacheOperationInvoker, java.lang.Object, java.lang.reflect.Method, java.lang.Object[])

从这里看出，是通过调用代理对象进行增强处理的。

而在当在checkCarInBlackListByCache 方法里面调用get方法时，依然是旧对象，还不是代理对象，因此需要重新注入新的代理对象调用。才能保证get方法可以获取到缓存的数据。最终通过引入新的注入对象，进行调用

ParkingBlackListBO parkingBlackListBO = parkingBlackListService.get(id);

问题得到解决