MyBatis PageHelper 使用踩坑

<dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper</artifactId>
    <version>5.1.10</version>
</dependency>

@Override
   public Result<PageResult<OrderResult>> queryOrderList(QueryOrderParam param){
      QueryWrapper queryWrapper = new QueryWrapper();
      Page<Object> page = PageHelper.startPage(param.getPageNum(), param.getPageSize());
      List<OrderMain> orderMainList = orderMainMapper.selectList(queryWrapper);
      List<OrderResult> resultList = new ArrayList<>();
      orderMainList.forEach(item->{
         OrderResult orderResult = new OrderResult();
         BeanUtils.copyProperties(item,orderResult);
         resultList.add(orderResult);
      });

      PageResult<OrderResult> pageResult = new PageResult<>(param.getPageNum()
              , param.getPageSize(), page.getTotal(), resultList);
      return Result.success(pageResult);
   }

<dependency>
   <groupId>com.github.pagehelper</groupId>
   <artifactId>pagehelper-spring-boot-starter</artifactId>
   <version>1.4.2</version>
</dependency>