What code have you already written? It's hard to give you helpful advice if you don't show us what you have accomplished already. Please help us to help you better by showing us the relevant code, the input you give and the output you get. Please also explain what output you expect instead.

I recommend decoding all your input to UTF-8 and then using the UTF-8 properties to extract the Chinese glyphs. Do note that the "Chinese" glyphs overlap with the Japanese glyphs etc., but at least some pages point to "Unihan" as the list of glyphs that is likely to be of use. Also see Unihan.