fix deepcopy middleware not success
####Version 1.7.18
- Bug fix: fix deepcopy middleware not success
- 2021-04-20 13:00 at ShangHai
####Version 1.7.17
- Bug fix: fix GetRandString return same result
- 2021-01-29 08:00 at ShangHai
####Version 1.7.18
####Version 1.7.17