Today, I used npoi to export excel, and the data was more than 30000. After waiting for five or six minutes, I didn’t finish the export. After debugging, I found that the bottleneck was in the method of autosizecolumn(), which was searched on the Internet https://bz.apache.org/bugzilla/show_ bug.cgi?id=58896 The topic of discussion is that when there is cell merging, the efficiency of autosizecolumn() will be super super super invincible and low. As for the parameter usemergedcells, it seems that it has no effect.
Now only use setcolumnwidth to adjust the width, no problem, very fast.