Can I get 2 transit visas in the span of 5 days?

I will be flying Dubai-Shanghai-Bangkok-Shanghai-Toronto. The first stop in SH is for 6 hours. Then, four days later, I have an overnight stop-over in SH before I fly to my final destination. Can I get a transit visas for both the 6-hour and the overnight stop-overs? I'm a Canadian passport holder.