I am a foreign student in Japan and would like to attend a conference in Beijing

Th consulate-general listed above are all open.
Which specific one do you refer to know their opening time? Usually, the processing days are around 4 days. So you will get it four days later.

You need to provide your valid passport, your application form with recent taken photo, your residence card, your invitation letter from the conference for application. I heard you may need to apply through local tour agency since you live in Japan for a long time and you are still suggested to consult the local Chinese embassy or consulate.