1. mapper 层返回的 List 的泛型和 service 层返回的PageInfo 的泛型类型一致：

@Override
public PageInfo<VO1> queryVO1List(String startTime,String endTime,Integer pageNum,Integer pageSize) {boolean pageStarted = false;try {PageHelper.startPage( pageNum,pageSize );pageStarted = true;List<VO1> vo1List = this.xxxMapper.queryVO1List( startTime,endTime );if( vo1List == null || vo1List.size() == 0 ){return new PageInfo<VO1>(new ArrayList<>(0));}return new PageInfo<VO1>( vo1List );} catch (Exception e) {log.error(Constants.EXCEPTION_LOG_PREFIX,e);return new PageInfo<VO1>(new ArrayList<>(0));}finally {if( pageStarted ){PageHelper.clearPage();}}
}

2. mapper 层返回的 List 的泛型和 service 层返回的 PageInfo 的泛型类型不一致：

@Override
public PageInfo<VO2> queryVO2List(String startTime,String endTime,Integer pageNum,Integer pageSize) {boolean pageStarted = false;try {PageHelper.startPage( pageNum,pageSize );pageStarted = true;List<VO1> vo1List = this.xxxMapper.queryVO1List( startTime,endTime );if( vo1List == null || vo1List.size() == 0 ){return new PageInfo<VO2>(new ArrayList<>(0));}PageInfo<VO1> pageInfo_vo1 = new PageInfo<>(vo1List);List<VO2> vo2List = this.vo1ListToVO2List( vo1List );PageInfo<VO2> pageInfo_vo2 = new PageInfo<>();pageInfo_vo1.setList( null );BeanUtils.copyProperties( pageInfo_vo1,pageInfo_vo2 );pageInfo_vo2.setList( vo2List );return pageInfo_vo2;} catch (Exception e) {log.error(Constants.EXCEPTION_LOG_PREFIX,e);return new PageInfo<VO2>(new ArrayList<>(0));}finally {if( pageStarted ){PageHelper.clearPage();}}
}