It depends on exactly what you’re needs are. If you’re earning money in China, then use that, and bring the excess cash home with you (or send it via bank transfer). If you mean you’ll need to convert euros to Chinese RMB, that is easy to do at almost any bank. You might also be able to use your bank card here in China to withdraw funds from your Dutch bank account. In general, getting money into China is easy, getting it out is not always so simple.