/ goods/:id 
 / user/:id 
 if id does not exist, how can I jump to 404 or other pages? 
 it will not be linked normally. What if the id result on url does not have this id? 
 I will ask for details when I am in created (). You can judge here to jump if not. 
 but I have a lot of such routes. Do I have to judge each one? 
