Combine the oyster sauce, Shaoxing, potato starch, soy sauce, white pepper and salt in a small bowl and whisk together.
Heat a large frying pan over medium high heat. Add the sesame oil and ginger and fry until fragrant. Add the ground pork and stir-fry, using the edge of a spatula to break up the meat into little crumbs.
When the meat is cooked, add the onion, carrot, celery, and shiitake mushrooms and continue stir-frying until the carrots are mostly cooked. Add the napa cabbage and glass noodles and continue stir-frying until the cabbage is mostly cooked. Add the sauce and stir-fry until there is no liquid left. Let this mixture cool.
Make some glue by combing 3 tablespoons flour with 3 tablespoons water.
Peel the wrappers and spread them out as pictured with about 1/2" of the wrapper below showing. This makes it easy to paint glue on several wrappers at once. Spread the glue with a pastry bush along the top edges of the wrapper.
Place about 1/3 cup of the room temperature filling about 2 inches above the bottom corner of the wrapper.
Tightly roll the wrapper and filling half-way.
Fold the left edge over right up against the edge of the filling, then fold the right edge over. The trick here is to taper your fold slightly so that the open flap is a little narrower than the bottom of the roll as this will create a good seal and prevent flaps of dough that will invite oil into your roll. It should look a bit like an open envelope at this point.
Finish by continuing to roll until the flap seals itself against the roll.
To make the sweet and sour sauce, whisk together the water, vinegar, sugar, ketchup, potato starch and salt in a small saucepan until there are no lumps. Bring the mixture to a boil stirring constantly until your sauce has thickened.
Prepare a paper towel lined rack. Pour about 2" of vegetable oil into a heavy bottomed pot and heat to 320 degrees F.
Fry the springrolls a few at a time, being careful not to overcrowd the pot. Turn them over frequently so that they brown evenly. When they reach an even tan color, transfer the spring rolls to your rack and allow them to drain. Repeat with the rest of the spring rolls.