Canadian Citizen - do I need a visa

travelling from Toronto to Shanghai Pudong eta Feb 4 4 pm then 3-1/2 days Shanghai tourist and 2 courtesy
business visits , then flight Shangha Pudong i to BKK Thailand on Feb 7 630 pm
same thing on return visit WEd Feb 15 BKK/Shanghai/Toronto but this time direct transit (less than 24 hours, no lay over , no visits)
can I enter China without an entry permit?? thank you Hans in Canada