增加BaseService四个通用方法：
List<Record> selectByExampleWithBLOBsForStartPage(Example example,
Integer pageNum, Integer pageSize);
List<Record> selectByExampleForStartPage(Example example, Integer
pageNum, Integer pageSize);
List<Record> selectByExampleWithBLOBsForOffsetPage(Example example,
Integer offset, Integer limit);
List<Record> selectByExampleForOffsetPage(Example example, Integer
offset, Integer limit);