In China, the standard electrical voltage is 220V, 50HZ.

Check you devices first. Some may be dual voltage and require an adapter only, not a converter. If your camera recharger is labeled "100-240V", then all you need is a cheap adapter that matches the electrical outlet prongs of the specific country.

Your hairdryer might be an exception, while most of the 3-5 star hotels in China will offer 110v electrical outlets at the toilet of your hotel room. And if you don't bring it, it is fine as most of star-rated hotels will offer hairdryers in your room. Or you can borrow one from the reception desk.