1 hour ago, JoNorvelleWalker said:My granddaughter reports that in her three visits spring rolls were common in China. She adds that it could be a case of catering to foreigners.
Spring rolls (春卷 - chūn juǎn) are common* (but not with mustard); it's egg rolls which aren't known. The spring roll sales aren't catering for foreigners - many of my local restaurants have them, but I'm the only foreigner in the city and rarely eat them.
*particularly right now as we are in the middle of the Spring Festival (Feb 12th-26th this year)