Dutch citizen in Japan wants Chinese visa

I am going to Japan where I can stay 89 days. I don't need a visa for Japan because I am invited as a scientific researcher. At the last day I go to Shanghai for 1 week for family visit. Then I fly back to Tokyo and from there I fly back to the Netherlands. When I order a tourist L, it will be ended at the last day in Japan so I can't go. Who knows how to handle?